MEMCAL 

LEIEMA1&Y 


ANATOMY  FOR  NURSES 


A  TEXTBOOK  OF 

ANATOMY  FOE  NURSES 


BY 

WILLIAM  GAY  CHRISTIAN,  M.D., 

Professor   of  Anatomy,    Medical    College   of   Virginia,    Richmond. 


WITH    THIETY-FOUE    OEIGINAL   ILLUSTBATIONS, 
FIVE  OF  WHICH  AEE  IN  COLOES 


ST.   LOUIS 

C.  V.  MOSBY  COMPANY 

1917 


K*,- 


COPYRIGHT,  1917,  BY  C.   V.   MOSBY  COMPANY 


F   r  f  fre  ; Press  of 

Company 


Q.M  £6 


DEDICATED 
TO  THE  MEMORY  OF 

EDITH  CAVELL 

WHO  DIED  FOR  HER  FRIENDS 


5664 


PREFACE 

I  have  written  this  book  because  I  have  found  the 
existing  textbooks  on  the  subject  unsatisfactory.  I 
believe  pupil  nurses  should  be  shown  the  various  tis- 
sues and  organs  of  the  body  and  that  this  work  should 
be  done  before  they  enter  hospitals  for  their  profes- 
sional training.  This  can  be  readily  accomplished  if 
the  medical  colleges  will  offer  a  brief,  practical  course 
in  anatomy  during  the  vacation.  Such  a  course  should 
occupy  not  more  than  three  or  four  weeks.  From  two 
to  three  hours  a  day  of  laboratory  instruction,  using 
prepared  dissections,  might  be  profitably  employed. 

I  fear  that  I  may  have  made  the  book  too  elaborate, 
but  teachers  can  readily  omit  descriptions  given  in  too 
much  detail. 

The  illustrations  have  been  drawn  by  Miss  Helen 
Lorraine  from  specially  prepared  dissections,  and  ap- 
pear to  me  exceptionally  well  done.  They  are  in  many 
instances  designedly  diagrammatic. 

W.  G.  C. 

Medical  College  of  Virginia, 
Richmond,  Va. 


CONTENTS 

CHAPTER  I 


INTRODUCTION 

CHAPTER  II 
OSTEOLOGY -  ••      2l 

CHAPTER  III 

A.RTHROLOGY          ^ 

CHAPTER  IV 
MYOLOGY 6' 

CHAPTER  V 
SPLANCHNOLOGY 9( 


CHAPTER  VI 
ARTERIES  AND  VEINS 107 

CHAPTER  VII 
THE    NERVOUS    SYSTEM 140 

CHAPTER  VIII 
ORGANS  OF  THE  SENSES 169 


CHAPTER  IX 

HISTOLOGY 


ILLUSTRATIONS 

FIG.  PAGE 

1.  Profile     of     skeleton 21 

2.  Typical   vertebra,   view   from   side 24 

3.  Typical  vertebra,  view  from  above 25 

4.  Front   view  of   skull 46 

5.  Base  of  skull,  upper  surface 48 

6.  Base  of  skull,  lower  surface 49 

7.  Pelvic  ligaments  and  capsule  of  hip     .......  65 

8.  Muscles.     Front  of  neck,  trunk,  and  upper  extremity     .  69 

9.  Orbital  muscles 76 

10.  Muscles.     Back  of  trunk,  upper  extremity,  and  hips     .     .  78 

11.  Front  view  of  organs.     Semi-diagrammatic 95 

12.  Diagram  of  entire  circulation 110 

13.  The  aorta  and  its  branches 114 

14.  Superior  mesenteric  artery 116 

15.  Diagram  of  arteries  and  veins  of  upper  extremity.     .     .  126 

16.  Diagram  of  arterial  circulation  in  lower  extremity     .     .  130 

17.  Brain,    lateral    view 143 

18.  Brain,     mesial    view 145 

19.  Larynx,    anterior    view 180 

20.  Larynx,    inside    view 182 

21.  Simple    tissues 188 

22.  Human    cartilage    cells 191 

23.  Hyaline   cartilage 191 

24.  White  nbrocartilage 193 

25.  Elastic  cartilage 194 

13 


14  ILLUSTRATIONS 

FIG.  PAGE 

26.  Nucleated  bone  cells,  etc. 195 

27.  Transverse   section   of    compact   tissue   of   bone   greatly 

magnified 196 

28.  Section  parallel  to  the  surface  from  the   shaft   of  the 

femur        197 

29.  Vertical  section  of  human  spleen  low  power     ....  205 

30.  Cross  section  of  pancreatic  tubule 206 

31.  Portion  of  transverse  section  of  human  liver     ....  208 

32.  Injected  lacteal  vessels  in  two   villi  of  human  intestine  212 

33.  Diagrammatic  representation  of  the  course  of  the  urinif- 

erous  tubules  and  the  kidney  vessels     .     .     .     .  .  .  214 

34.  Diagram  of  the  ending  of  a  bronchial  tube     ....  217 


ANATOMY  FOR  NURSES 


ANATOMY  FOR  NURSES 


CHAPTER  I 
INTRODUCTION 

The  only  knowledge  of  anatomy  which  is  perma- 
nently retained  is  that  which  is  seen  or  felt.  Names 
are  comparatively  unimportant,  but  must  be  employed 
to  prevent  confusion,  to  enable  one  to  impart  wrhat  is 
known  and  to  facilitate  such  studies  as  physiology, 
pathology  and  surgery.  Certain  terms,  frequently  em- 
ployed, must  be  explained  and  comprehended  before 
the  study  can  even  be  begun. 

The  entire  body  is  conceived  of  as  a  cube,  and  hence 
would  have  six  faces  which  would  be  directed  up- 
ward, downward,  forward,  backward  and  to  either 
side.  The  first  four  are  easy  of  comprehension;  but 
the  two  lateral  confuse  us  because  there  are  two  arms 
and  two  legs,  distinguished  as  right  and  left,  each 
itself  having  two  surfaces  wrhich  cannot  receive  these 
familiar  names,  because  the  right  side  of  the  left  arm 
has  all  the  peculiarities  of  the  left  side  of  the  right; 
and  there  must  be  a  name  for  this  symmetrical  appear- 
ance. Hence,  the  body  may  be  considered  as  split  by 
an  imaginary  plane  drawn  from  the  middle  of  the  top 
of  the  head  down  between  the  feet.  Such  an  imagi- 
nary plane  or  line  would  add  a  face  which  would  be 
directed  toward  the  midline  and  would  be  called  the 

17 


18  ANATOMY    FOR    NURSES 

mesial  or  inner  face.  The  mesial  or  inner  faces  of  the 
arms  or  legs  are  exactly  alike,  while  the  parts  which 
are.  directed  away  from,  the  midline  are  the  lateral  or 
outer  faces  and  are  also  alike. 

Practically  all  anatomical  names  were  given  when 
Latin  or  Greek  were  the  only  languages  in  which 
learning  was  concealed.  The  names  which  are  here 
employed  and  which  have  the  great  convenience  of 
being  intelligible  to  anatomists  all  over  the  world, 
are  of  Latin  or  Greek  origin.  These  names  are  em- 
ployed in  surgical  and  medical  works,  as  well  as  in 
anatomy.  Such  terms  as  front,  back,  etc.,  are  not 
usually  used,  but  words  of  Latin  origin  with  the  same 
significance  as  follows:  Upward  is  superior,  downward 
is  inferior,  forward  is  anterior,  backward  is  posterior, 
inward  is  medial,  and  outward  is  lateral. 

So  far  only  the  faces  of  a  cube  which  have  one 
definite  direction  have  been  considered,  while  some 
of  the  cube  may  be  turned  to  face  partly  in  two 
directions.  These  oblique  portions  are  designated  by 
compound  wrords  indicative  of  the  twro  directions  in- 
volved, thus:  Antero-superior  would  be  facing  forward 
and  upward;  antero-median,  forward  and  inward;  an- 
tero-lateral,  forward  and  outward,  etc. 

If  a  pencil  is  placed  upright  on  a  table,  point  up- 
ward, the  pencil  will  be  a  line  at  right  angles  to  the 
plane  of  the  table,  and  its  point  will  be  in  the  direc- 
tion in  which  the  table  top  faces ;  i.  e.,  it  is  the  superior 
surface  of  the  table.  The  names  for  many  appear- 
ances in  the  body  may  be  determined  in  just  that 
way.  Put  the  part,  ab6ve  for  instance,  in  its  ana- 
tomical position,  and  then  place  a  pencil  on  the  various 


INTRODUCTION 


19 


parts  of  the  bone  just  as  on  the  table.  If  properly 
placed,  the  pencil  will  point  in  one  of  the  six  cardinal 
directions  or  to  some  angle  between  two  or  more  of 
them.  This  Avill  be  the  direction  of  that  part  and 
probably  a  portion  of  its  name. 

The  anatomical  position  is  not  the  natural  posi- 
tion of  the  body.  If  one  stands  at  ease  he  will  find 
that  the  arms  swing  at  the  sides  with  the  thumbs 
nearly  on  the  thighs,  the  fingers  partly  bent  and  the 
toes  turned  out  a  little.  Now  turn  the  hands  until 
the  little  fingers  touch  the  thighs,  thumbs  outward, 
fingers  straight,  heels  and  big  toes  touching,  head  up 
and  eyes  looking  straight  in  front.  This  is  the  ana- 
tomical position.  In  it  every  portion  of  the  body  must 
be  placed  before  it  can  be  properly  studied,  and  in  it 
one  must,  in  imagination,  place  every  person  and  part 
of  a  person,  until  the  mind  unconsciously  perceives 
them  only  in  that  awkward  attitude. 

Only  the  broad  faces  of  the  cube  have  thus  far  been 
considered.  It  has,  however,  narrow  lines,  or  borders, 
and  sharp  points,  or  angles,  separating  these  faces. 
In  anatomical  language  the  faces  are  surfaces,  the 
lines  borders,  the  points  angles,  spines  or  processes. 
It  is  chiefly  in  the  study  of  the  bones  and  viscera  that 
these  terms  are  employed.  Other  technical  terms  will 
be  explained  as  they  occur. 


CHAPTER  II 
OSTEOLOGY 

The  bones  form  the  framework  of  the  body.  They 
are  somewhat  more  than  two  hundred  in  number  and 
vary  greatly  in  size  and  function.  Those  of  the  ex- 
tremities are  chiefly  a  set  of  levers,  actuated  by  mus- 
cles and  bound  together  by  ligaments,  the  entire  ap- 
paratus being  designed  for  support  and  to  produce 
motion  of  some  sort.  Others  serve  to  more  or  less 
perfectly  surround  cavities  which  contain  important 
organs,  while  their  exterior  faces  give  firm  points  of 
attachment  to  muscles  and  ligaments.  Roughly 
bones  may  be  divided  into  two  classes  by  the  presence 
or  absence  of  marrow  cavities:  those  having  such  cavi- 
ties are  called  long;  and  those  without  the  cavities,  ir- 
regular bones.  The  irregular  bones  consist  more  or 
less  completely  of  two  plates  or  tables  bound  together 
by  numerous  minute  bands  of  bone  with  spaces  be- 
tween, forming  a  network  not  unlike  sponge.  Both 
varieties  are  covered  by  a  delicate  membrane,  the  per- 
iosteum, which  contains  a  large  number  of  blood  ves- 
sels and  is  the  tissue  to  which  ligaments  and  muscles 
are  really  attached.  The  long  bones  are  found  chiefly 
in  the  extremities,  while  most  of  the  irregular  bones 
are  in  the  skull  and  spinal  column,  though  the  hands 
and  feet  each  contain  several  bones  of  this  variety. 

The  term  extremity  is  applied  to  what  is  usually 
called  arm  and  leg.  In  anatomical  language  the  up- 

20 


OSTEOLOGY 


21 


—Skull 


— Cervical  vertebrae 


— Scapula 


— Scapula 


— Lumbar  vertebrae 


v— Pelvis 


.  ,~r — Femur 


Fig.  1. — Profile  of  skeleton. 


ANATOMY   FOR   NURSES 

per  extremity  comprises  all  the  structures  from  the 
tips  of  the  fingers  to  the  attachment  of  the  collar  bone 
to  the  breast  bone,  while  the  lower  extremity  extends 
from  the  toes  to  the  pelvis,  including  the  hips.  The 
upper  is  divided  into  shoulder,  arm,  forearm,  and  hand; 
the  lower  into  hip,  thigh,  leg  and  foot.  The  term 
arm,  therefore,  is  correctly  used  only  for  that  portion 
of  the  upper  extremity  extending  from  the  shoulder  to 
the  elbow;  while  leg  is  that  part  from  knee  to  ankle. 
The  remaining  portions  of  the  body  comprise  the  head, 
neck,  and  trunk,  the  neck  insensibly  blending  with  the 
upper,  and  the  trunk,  or  body,  with  the  lower  ex- 
tremity. 

THE   VERTEBRAL,    OR   SPINAL,    COLUMN 

The  spinal,  or  vertebral  column,  binds  the  head  to  the 
neck,  forms  the  middle  and  posterior  part  of  the  lat- 
ter and  of  the  trunk,  and  finally  binds  the  trunk  to 
the  extremities  and  the  two  lower  extremities  to  each 
other.  It  contains  a  central  canal  for  the  spinal  cord 
and  is  so  important  that  it  is  properly  the  first  object 
of  our  study.  At  an  early  period  of  life  it  consisted 
of  thirty-three  pieces  of  bone  called  vertebrae  (from  a 
Latin  word  meaning  to  turn,  because  turning  or  twist- 
ing the  body  from  side  to  side  is  accomplished  at  the 
joints  between  these  bones) ;  but,  in  adult  life,  nine  of 
these  pieces  have  fused  together  in  such  a  way  as  to 
constitute  two  pieces,  so  that  the  total  number  of 
vertebrae  is  now  twenty-six.  Of^these,  seven  are  found 
in  the  neck  and  are  called  cervical :  twelve  form  the 
posterior  wall  of  the  cavity  containing  the  heart  and 
lungs,  thoracic  cavity,  and  are  called  thoracic  verte- 


OSTEOLOGY  23 

brae  for  that  reason,  dorsal  because  they  form  a  large 
part  of  the  back;  five  are  found  in  the  " small  of  the 
back"  and  are  called  lumbar,  or  abdominal  from  form- 
ing the  middle  of  the  posterior  wall  of  the  abdominal 
cavity.  The  remaining  two,  sacrum  and  coccyx,  are  in 
the  pelvis  and  are  called  the  pelvic  vertebrae. 

A  Typical  Vertebra 

With  certain  important  exceptions,  every  vertebra 
consists  of  a  large  central  hole  (foramen,  opening), 
the  vertebral  foramen,  surrounded  Tby  a  solid  mass  of 
bone  in  front  called  the  body,  two  short  rounded  pro- 
jections running  backward  one  from  either  side  of  the 
body,  the  pedicles,  which  terminate  in  flattened,  broad 
sheets  of  bone  which  run  backward  and  inward  until 
they  meet,  the  laminae,  whose  union  forms  a  projection 
of  varying  size,  shape  and  direction,  the  spine,  or  spi- 
nous  process.  In  addition  to  these  appearances  there 
are  four  projections,  two  running  upward  and  two 
downward,  by  which  the  vertebrae  are  joined  together, 
known  as  'articular  processes,  because  the  joints,  or 
articulations,  formed  by  their  union  permit  move- 
ment, and  are  distinguished  as  superior  and  inferior; 
and  two  lateral  projections,  one  on  either  side,  form- 
ing levers  to  which  muscles  can  be  attached  by  which 
the  vertebra  may  be  moved.  These  processes  are  called 
transverse  firom  their  direction.  Above  and  below 
each  pedicle  is  a  notch,  intervertebral,  which  becomes 
an  intervertebral  foramen  when  two  vertebrae  are  ar- 
ticula^ted,  to  transmit  the  spinal  nerves. 

In  the  several  regions  of  the  column  the  component 
parts  of  the  vertebrae  differ  sufficiently  to  enable  us 


24  ANATOMY   FOR   NURSES 

to  distinguish  a  vertebra  of  one  region  from  that  of 
another. 

In  the  cervical  region  the  body  is  small,  has  a  pro- 
jecting lip  on  either  side  above  and  a  notch  in  front. 
Below  it  has  a  notch  on  either  side  and  a  lip  in  front. 

In  the  thoracic  region  the  ~body  has  no  lips,  is  nearly 


Sup.  articular  process 

— Transverse  process 


— Inf.  articular  process 


— Spinous  process 


Fig.   2. — Typical  vertebra,   view   from  side. 

round,  and  has  either  a  whole  or  a  half  facet  (articular 
surface)  for  the  head  of  a  rib. 

In  the  lumbar  region  the  body  has  neither  facet  nor 
lips.  Except  that  they  increase  in  size  from  above 
downward,  the  pedicles  have  little  to  distinguish  them. 

The  lamince  are  large  in  proportion  to  the  size  of  the 
bone  in  the  cervical  and  thoracic  regions  and  occupy 
less  of  the  bone  in  the  lumbar. 


OSTEOLOGY 


25 


The  spines  are  short  and  forked  (bifurcated)  in  the 
cervical  region ;  long,  triangular,  pointed,  and  run  nearly 
downward  in  the  thoracic;  and  short  quadrilateral,  and 
very  large  in  the  lumbar. 


Body 


Pedicle— 


' — Sup.  articular 
process 


df*' 

*r^ 

Lamina 

^B — Spinous 


Transverse  process 


Spinous  process 


Fig.    3. — Typical  vertebra,   view   from   above. 

The  superior  articular  processes  look  upward  and 
backward  in  the  cervical,  backward  in  the  thoracic,  and 
inward  in  the  lumbar  region.  The  inferior  look  down- 


26  ANATOMY   FOR   NURSES 

ward  and  forward  in  the  cervical,  forward  in  the  tho- 
racic, and  outward  in  the  lumbar. 

The  transverse  process  is  perforated  by  the  vertebral 
foramen  at  its  base  and  bifurcated  at  its  extremity  in 
the  cervical  region;  runs  outward  and  backward,  is 
club-shaped  and  bears  an  articular  facet  in  the  thoracic, 
and  is  sharp,  curved,  and  rib-like  in  the  lumbar. 

Peculiar  Vertebra 

The  first  cervical  is  called  the  atlas  and  has  no 
body.  Its  spinal  foramen  is  very  large.  It  has  five 
articular  processes  of  which  the  first  is  on  the  pos- 
terior face  of  its  anterior  part,  called  the  anterior 
arch.  The  two  superior  are  oval,  longer  from  before 
backward  than  from  side  to  side  and  look  upward. 
They  are  receiving  surfaces  for  a  condyle.  The  in- 
ferior look  downward  and  are  flat  and  circular.  The 
bone  has  no  spine,  Avhich  would  interfere  with  the 
movements  of  the  head  if  present,  and  is  the  connect- 
ing link  between  the  skull  and  spinal  column. 

The  second  cervical  is  called  the  axis.  It  is  pecu- 
liar on  its  upper  and  typical  on  its  lower  aspect.  It 
is  the  transition  vertebra.  On  its  body  above  is  a 
sharp  pointed  process,  called  odontoid  because  it  is 
like  a  tooth,  whose  anterior  face  is  articular  for  the 
similar  facet  on  the  back  of  the  front  part  of  the 
atlas.  This  upright  piece  is  a  pivot  or  axle  around 
which  the  atlas  revolves  in  turning  the  head  from 
side  to  side.  The  superior  articular  processes  look 
upward  and  are  round.  The  spine  is  very  large  and 
bifurcated  below. 


OSTEOLOGY  27 

THE  SACRUM  AND  COCCYX 

As  the  coccyx  is  often  ossified  to  the  sacrum  and 
is  always  articulated  with  it  so  that  the  two  act  nearly 
as  one  bone,  they  may  be  described  together. 

The  sacrum  forms  a  double  wedge  whose  apex 
is  prolonged  downward  by  the  coccyx  to  a  sharp 
point,  while  its  base  is  directed  upward  to  the  body  of 
the  fifth  lumbar  vertebra  whose  under  surface  it  ex- 
actly resembles.  Its  anterior  surface  is  concave  from 
side  to  side  and  from  above  downward,  so  as  to  in- 
crease the  capacity  of  the  pelvic  cavity,  whose  pos- 
terior wall  it  forms.  It  has  on  either  side  of  the  mid- 
line  a  vertical  row  of  loramina,  which  are  circular  and 
smooth  and  terminate"  laterally  in  shallow  grooves. 

The  posterior  surface,  much  narrower  than  the  an- 
terior, is  convex  in  both  directions.  It  shows  a  row 
of  tubercles  in  the  midline,  the  rudiments  of  spinous 
processes,  and  two  rows  of  foramina  smaller  and  less 
regular  than  those  on  the  front. 

On  each  side  the  bone  is  wide  above,  narrow  and 
rough  below.  Near  the  front  above  is  an  articular 
facet,  shaped  somewhat  like  an  ear  and  called  auri- 
cular.  This  is  to  articulate  with  a  similar  facet  on  the 
ilium. 

THE  RIBS  AND  THORAX 

The  bony  wall  of  the  chest  or  thorax  is  made  up  oi 
the  breast  bone,  or  sternum,  on  the  midline  in  front, 
and  the  front  of  the  dorsal  vertebrae  behind  with 
twelve  ribs  on  each  side. 

The   sternum   consisted   at   one   time   of   numerous 


28  ANATOMY   FOR   NURSES 

pieces,  as  the  sacrum  did,  which  have  coalesced  into  three 
called,  from  above  downward,  manubrium,  gladiolus, 
and  ensiform  cartilage.  It  may  conveniently  be  de- 
scribed as  a  single  bone,  large  above,  where  it  has  at 
each  corner,  or  angle,  a  saddle-shaped  articular  facet 
for  the  collar  bone  (clavicle),  which  is  the  only  bony 
link  between  the  trunk  and  the  upper  extremity,  and 
tapering  to  an  irregular  point  below.  It  is  slightly 
convex  in  front  and  concave  behind.  Each  lateral 
border  presents  pits  for  the  reception  of  the  cartilages 
which  bind  the  seven  true  ribs  to  the  sternum. 

The  ribs,  twelve  on  each  side,  are  much  curved  long 
bones  known  by  number  from  above  downward.  The 
first  seven  articulate  with  the  vertebral  column  and 
the  sternum,  and  are  hence  known  as  vertebro-sternal. 
The  next  three  are  indirectly  held  to  the  sternum 
through  attachment  to  the  cartilage  of  the  seventh, 
and  have  received  the  name  of  vertebro-cliondral;  while 
the  last  two  are  attached  to  the  vertebral  column  alone 
and  are  called  vertebral.  A  typical  rib,  like  a  typical 
vertebra,  possesses  certain  characteristics  common  to  all 
though  varying  in  degree.  Each  has  a  posterior  or  verte- 
bral, and  an /Anterior,  or  sternal,  extremity  and  a  shaft 
with  two  surfaces  and  two  borders.  On  the  vertebral  ex- 
tremity there  is  a  head  with  two  articular  facets,  sepa- 
rated by  a  transverse  ridge,  for  the  two  vertebrae  and  the 
intervertebral  disk  with  which  a  rib  articulates,  a  neck 
and  a  tubercle.  The  latter  is  also  marked  by  a  facet  for 
the  transverse  process  of  the  lower  of  the  two  verte- 
brae with  which  it  articulates.  The  posterior  part  of 
the  rib  runs  nearly  outward,  until  beyond  the  tubercle, 
when  it  turns  abruptly  forward  and  downward,  mak- 


OSTEOLOGY  29 

ing  the  bone  curved  in  two  directions;  i.  e.,  it  is  con- 
cave inward  and  less  concave  upward,  or  curved 
around  a  vertical  and  a  horizontal  axis.  The  anterior 
extremity  is  blunt  and  has  a  rather  deep  pit  for  the 
cartilage  which  binds  it  to  the  sternum. 

The  shaft  has  a  round  upper  and  a  sharp  lower  bor- 
der. Its  outer  surface,  which  is  convex,  is  rough  while 
the  inner  is  concave,  smooth,  and  marked  near  the  lower 
border  by  a  groove  running  three-fourths  the  length  of 
the  bone.  Where  the  double  curvature  occurs,  there  is 
a  ridge  marking  the  angle  of  the  bone. 

The  first  rib  is  the  most  peculiar  and  important.  It 
has  only  one  facet  on  its  head ;  its  surfaces  look  nearly 
upward  and  downward  and  its  borders  inward  and  out- 
ward. On  its  upper  surface  are  two  grooves,  separated 
by  a  slight  ridge,  for  the  subclavian  artery  and  vein. 
Other  ribs  are  also  called  peculiar,  but  only  the  elev- 
enth and  twelfth  need  be  noted.  They  are  called  false 
or  floating  ribs  because  they  are  fastened  at  but  one 
end.  Each  has  a  single  articular  facet  and  no  pit  for 
a  sternal  cartilage.  The  twelfth  is  the  guide  to  the 
kidney. 

The  Thorax 

The  chest  or  thorax  is  a  cone  opened  at  the  top  with 
its  base  downward.  The  projection  forward  of  the 
thoracic  verterbrae  makes  a  cross  section  of  the  cone 
heart-shaped.  As  the  ribs  increase  in  length  from  the 
first  to  the  seventh  and  their  anterior  extremities  are 
lower  than  the  posterior,  while  the  sternum  is  shorter 
than  the  thoracic  part  of  the  column,  it  follows  that 
the  chest  is  deeper  behind  than  in  front,  and  wider  at 


30  ANATOMY   FOR   NURSES 

the  bottom  than  at  the  top.  The  inclination  of  the  ribs 
has  an  important  bearing  on  the  movements  of  the 
chest  in  breathing.  The  spaces  between  the  ribs  are 
called  intercostal  and  are  filled  by  soft  tissue. 

THE  EXTREMITIES 

The  skeleton  of  the  upper  extremity  consists  of  the 
scapula  and  clavicle  forming  the  shoulder  girdle;  the 
humerus,  the  single  bone  of  the  arm;  the  radius  and 
ulna  of  the  forearm  and  numerous  bones  of  the  hand. 
That  of  the  lower  extremity  consists  of  the  os  innomina- 
tum  (nameless  bone)  forming  the  pelvic  girdle;  the 
femur,  the  single  bone  of  the  thigh;  the  tibia  and  fibula 
of  the  leg,  and  numerous  bones  of  the  foot. 

The  Shoulder  Girdle 

The  clavicle  or  collar  bone  is  a  long  bone  and,  like 
all  bones  of  that  class,  has  a  shaft  and  two  extremities, 
inner  or  sternal  and  outer  or  acromial.  It  runs  al- 
most horizontally  outward  from  the  upper  end  of  the 
sternum  to  the  acromioii  process  of  the  scapula. 

The  inner  extremity  is  rounded  and  marked  by  a 
saddle-shaped  (that  is  concavo-convex)  articular  facet; 
the  outer,  flattened  from  above  downward  and  marked 
by  an  oblong  facet  which  faces  outward  and  downward 
so  as  to  rest  on  the  acromion. 

The  shaft  is  prismoid  for  its  inner  two-thirds  and  flat 
for  its  outer  one-third.  It  is  convex  forward  for  its 
inner  two-thirds  and  concave  forward  for  the  outer 
third.  The  inferior  face  is  marked  by  a  depression, 
called  rhomboid,  where  it  is  fastened  to  the  first  rib, 


OSTEOLOGY  31 

and  a  shallow  groove,  running  outward,  called  subcla- 
vian.  The  upper  face  and  anterior  border  are  rounded, 
slightly  rough  and  can  be  made  out  by  the  finger,  ex- 
cept in  the  very  fat,  or  are  subcutaneous. 

The  Scapula. — This  is  an  irregular,  flat  triangular 
bone,  forming  the  posterior  and  bulkier  part  of  the 
shoulder  girdle.  It  has  anterior  and  posterior  faces; 
external,  internal,  and  superior  borders;  superior,  in- 
ferior, and  external  angles,  a  spine,  acromion  and  cora- 
coid  processes. 

The  anterior  face  has  one  large  hollow  for  lodging  a 
muscle,  while  the  posterior  has  two,  the  smaller  above 
and  the  larger  below  the  spine.  .  These  hollows  are 
known  respectively  as  the  sub scapular,  supraspinous 
and  infraspinous  fossce. 

k*V^-£  C\A-iJc_ 

The  internal  or  vertebral  border  is  long,  thin,  and 
lipped.  The  superior  is  short,  thin,  and  has  a  notch 
near  its  outer  end.  The  (mtew&f  or  axillary  is  thick 
and  rough,  giving  attachment  to  several  muscles. 

The  superior  and  inferior  angles  give  attachment  to 
muscles;  but  the  external  bears  a  pear-shaped  articu- 
lar cavity,  the  cjlenoid^  which  receives  the  humerus  and 
with  it  forms  the  shoulder  joint.  The  large  end  of  the 
cavity  is  below  and  it  is  very  shallow. 

The  spine  starts  near  the  vertebral  border  and,  ris- 
ing rapidly  above  the  level  of  the  bone,  terminates  in 
a  triangular  projection,  the  ncromion  process,  which 
overhangs  the  glenoid  cavity  and  protects  the  shoul- 
der joint  from  violence  directed  from  above  and  be- 
hind. The  surfaces  of  the  spine,  looking  upward  and 
downward,  form  the  floor  of  the  supraspinous  and  roof 


32  ANATOMY   FOR   NURSES 

of  the  infraspinous  fossa.  The  posterior  border  of  the 
spine  is  thick,  rough,  and  subcutaneous. 

The  acromion  process  has  on  its  inner  border  the 
articular  facet  for  the  clavicle. 

The  Qoracoid  process  lies  under  the  outer  third  of 
the  clavicle,  projecting  like  a  crooked  finger  over  the 
glenoid  cavity  from  its  upper  inner  aspect. 

The  Pelvic  Girdle 

The  Os  Innominatum. — The  innominate  or  nameless 
bone,  consisted,  in  fetal  life,  of  three  bones  called 
ilium,  ischium,  and  pubis,  which  are  united  in  the  ace- 
tabulum. 

The  ilium  is  the,  expanded  upper  part  of  the  bone 
presenting  an  external  surface  which  sup/ports  the 
great  muscles  of  the  hip  and  a  smaller  imernm  surface, 
also  lodging  muscles,  and  having  the  important  func- 
tion of  forming  a  large  part  of  the  false  pelvis.  Sur- 
mounting the  top  of  the  bone  is  a  sinuous  crest  which 
reaches  its  highest  point  about  the  junction  of  its  an- 
terior and  middle  thirds.  This  erect  can  n^e  felt,  ex- 
cept in  the  very  fat,  but  is  not  subcutaneous.  Many 
important  structures  are  located  1,^  reference  to  the 
crest,  whose  extremities  are  called  &  ^v^M*^and  posterior- 
superior  spinous  processes.  Below  each  point  is  a 
smaller  and  less  important  process  designated  inferior 
spinous  process — anterior  and  posterior. 

The  ischium,  by  the  greater  part  of  its  outer  face, 
forms  three-fifths  of  the  acetabulum,  while  its  inner 
face  forms  nearly  all  of  the  lateral  wall  of  the  pelvis, 
notably  its  inclined  plane.  The  posterior  face  is  the 
back  of  the  acetabulum.  The  lower  part  of  the  ischium 


OSTEOLOGY  33 

is  called  its  tuberosity,  upon  which  the  weight  of  the 
body  rest  when  one  sits  straight.  The  slender  anterior 
piece  of  bone  running1  up  from  the  tuberosity  and  form- 
ing part  of  the  boundary  of  the  tkyvmd  or  obturator 
foramen,  is  called  the  ramus  of  the  ischium. 

The  pubis  forms  the  most  anterior,  internal  and  least 
massive  part  of  the  bone.  Its  outer  end  is  the  innermost 
part  of  the  acetabulum,  its  inner,  which  is  rough  and  ir- 
regular, forms  the  union  between  the  two  innominate 
bones  (symphysis  pubis).  The  posterior  face  is  the  an- 
terior wall  of  the  pelvis,  while  the  anterior,  somewhat 
rough,  gives  attachment  to  several  muscles. 

Its  superior  border  is  broad  and  rounded  and  marked 
near  the  inner  end  by  a  prominent  spine  which  is  one 
of  the  most  important  points  of  departure  in  measure- 
ments around  the  hip  joint,  pelvis  and  abdomen.  The 
lower  border  is  an  oblique  groove  which  forms  the  upper 
boundary  of  the  thyroid  foramen.  Q  /^  ~JL  c\/x*^r^  d*~ 

The  acetabulum  (a  vessel  for  holding  vinegar)  is 
analogous  to  the  glenoid  cavity  of  the  scapula,  but 
much  deeper.  Its  bottom  is  a  nonarticular  notch  and 
the  lower  inner  part  of  the  prominent  rim  is  wanting. 
The  articular  part  is  the  interior  of  the  rim. 

The  obturator  foramen  is  somewhat  triangular,  more 
so  in  women  than  in  men,   and  is  found  between  the 
body  of  the  pubis  above,  that  of  the  ischium  externally    jc^ TVl 
and  the  rami  of  the  two  internally.       ^^^wjJA 

THE  PELVIS 

The  deep  cavity  formed  by  the  ossa  innominate, 
sacrum  and  coccyx  is  the  pelvis.  The  expanded  flank 


34  ANATOMY    FOR    NURSES 

bones,  or  ilia  seem  to  stop  at  a  prominent  ridge  or 
line  below  which  the  pelvis,  or  deep  basin,  suddenly 
contracts.  This  line,  extending  along  the  top  of  the 
pubis,  across  the  ilium  and  on  to  the  sacrum,  is  called 
the  ileo-pectineal.Q,.  All  that  lies  above  it  is  the  false 
and  all  below  the  true  pelvis.  The  true  pelvis  is 
deepest  behind  and  on  the  sides  and  very  shallow  in 
front.  The  posterior  wall  is  the  hollow  of  the  sacrum, 
the  lateral  Avails  the  inclined  plane  or  inner  face  of 
the  ischium,  while  the  front  is  formed  by  the  union 
of  the  pubic  bones. 

The  opening  from  the  abdomen,  marked  off  by  the 
ileo-pectineal  line,  is  called  the  inlet;  the  lower,  irregu- 
lar opening,  is  the  outlet,  because  the  child  in  being  born 
enters  from  above  and  passes  out,  or  is  born  through 
the  lower  opening.  It  will  be  seen  that  the  inlet  is  a 
dense  ring  of  firmly  united  bones,  while  the  outlet  is 
made  up  of  three  deep  notches,  anterior  and  two  lateral, 
with  a  flexible  joint — between  sacrum  and  coccyx — in 
the  middle  behind.  The  female  pelvis  is  much  more  ca- 
pacious than  the  male,  is  not  so  deep  but  wider,  and  the 
pubic  arch  is  particularly  wide. 

The  pelvic  girdle  binds  the  lower  extremities  to  the 
trunk  as  the  shoulder  girdle  does  the  upper.  The  former 
is  designed  to  support  the  weight  of  the  body,  the  lat- 
ter to  carry  out  a  great  variety  of  movements.  The 
first  is  designed  primarily  for  strength,  the  latter  for 
grace  and  freedom.  Hence  it  will  be  observed  that  the 
shoulder  girdle  is  given  all  the  strength  consistent  with 
perfect  freedom  of  movement,  w^hile  the  pelvic  girdle 
has  all  the  freedom  of  movement  consistent  with  great 
strength. 


OSTEOLOGY  35 

HUMERUS  AND  FEMUR 

These  bones  have  many  features  in  common  which 
should  be  compared.  Both  are  long  bones  and,  of 
course,  each  has  a  shaft  and  two  extremities. 

The  Humerus 

The  upper  extremity  of  the  humerus  has  a  nearly 
hemispherical  head  which  looks  upward,  inward  and 
backward,  separated  from  the  remainder  of  the  bone 
by  a  circular -groove  called  the  anatomical  neck.  Ex-  - 
tergal  to  this  are  two  tuberosities,  internal  or  JLesser 
and  external  or  greater,  separated  by  a  deep  vertical 
groove,  the  Mcipital.  Below  the  tuberosities  the  up- 
per extremity  diminsh.es  to  the  circumference  of  the 
shaft,  this  portion  being  called  the  surgical  neck. 

The  lower  extremity  is  flattened  and  much  wider 
from  before  backward  than  from  side  to  side.  A  little 
above  the  termination  of  the, bone  a  projection  on  each 
side,  improperly  called  al^cbndyle,  inner  and  outer, 
presents  strong  subcutaneous  attachments  for  muscles 
of  the  forearm.  The  inner  of  these  tuberosities  is 
much  larger  than  the  outer,  while  of  the  ridges  leading 
upward  from  the  condyles,  the  outer  is  the  more  promi- 
nent. The  remainder  of  this  extremity  shows  a 
rounded  articular  surface  ( capitulum  humeri)  for  the 
radius  outwardly  and  a  trochlear  surface  for  the  sig- 
moid  cavity  of  the  ulna  inwardly.  A  trochlea  is  a 
pulley;  i.  e.,  a  depression  with  a  ridge  on  each  side, 
like  the  grooved  wheel  in  which  a  sash  cord  runs.  A 
deep  depression  behind  and  a  shallow  one  in  front, 
above  the  trochlea,  receive  the  olecranon  and  cora- 


36  ANATOMY   FOR   NURSES 

uoid  processes  of  the  ulna  in  extension  and  flexion, 
respectively,  and  bear  the  names  olecranon  and  cora- 
noid  fossae. 

The  shaft  is  somewhat  three  sided  in  the  middle,  cir- 
cular above,  and  nearjy  flat  below.  The  bicipital  groove 
expands  into  the  kwier  race;  the  outer  has  a  rough  im- 
pression for  the  deltoid  muscle  about  half  way  down, 
while  both  posterior  and  outer  are  furrowed  by  a 
groove,  the  musculo-spiral  which  lodges  a  nerve  of 
that  name.  The_rMg$s  bounding  the  bicipital  groove 
are  called  internal  or  anterior  and  external  bicipital 
ridges. 

The  Femur 

The  nearly  spherical  head  of  the  femur  is  set  on  an 
oblique  constricted  projection  of  bone  which  corre- 
sponds to  the  anatomical  neck  of  the  humerus.  This 
is  called  the  neck  of  the  femnr  and  so  supports  the 
round  head  as  to  make  it  face  upward,  inward,  and 
forward.  The  head  has  a  little  nonarticular  depres- 
sion near  its  center.  The  neck  is  shorter  above  than 
below  and  is  flattened  from  before  backward.  Ex- 
ternally the  neck  terminates  at  a  quadrilateral  tu- 
berosity  called  the  great  trochanter  (meaning  to 
turn)  which  projects  above  the  neck,  gives  attach- 
ment to  many  muscles  and  is  an  important  landmark 
about  the  hip,  easily  felt  though  not  subcutaneous. 
Below  and  internal  to  the  greater  is  a  sharply  promi- 
nent lesser  trochanter.  The  two  are  connected  by 
lines  or  ridges  called  intertrochanteric. 

The  lower  extremity  is  much  larger  than  the  upper. 
A  rough  prominence  on  each  side  is  called  a  tuberosity, 


OSTEOLOGY  37 

*JM       L/VuJ? 

mteiial  and  external,  while  the  bottom  is  occupied  by 
two  oblong,  oval,  convex  articular  projections  called 
eondyles.  These  are  separated  behind  by  a  deep  11011- 
articular  notch,  the  intercondyloid,  and  united  in  front 
by  a  trochlear  surface  for  the  patella.  The  extremity 
is  somewhat  flattened. 

The  shaft  is  bowed  so  as  to  be  convex  forward.  It 
is  so  nearly  cylindrical  that  borders  are  nearly  indistin- 
guishable except  the  posterior,  called  linea  aspera  (rough 
line)  which  gives  attachment  to  a  large  number  of  mus- 
cles. It  breaks  up  below  into  two  lines  which  divide  to 
bound  a  triangle  called  popliteal.  Above  the  linea  aspera 
runs  to  the  trochanters  m  three  divisions. 

The  femur  is  much  larger  than  the  humerus,  its 
head  more  globular,  its  anatomical  neck  longer,  all 
points  showing  it  is  designed  for  power  and  not  mobility. 

THE  RADIUS 

The  radius  is  the  outer  and  smaller  of  the  two  bones 
of  the  forearm  and  increases  in  size  from  above  down- 
ward. 

The  upper  extremity  has  a  head  consisting  of  a  sau- 
cer-like cavity  for  the  radial  head  of  the  humerus, 
surrounded  by  and  continuous  with  an  articular  rim 
for  the  lesser  sigmoid  cavity  of  the  ulna.  Below  this 
is  a  constricted  necjc,  the  smallest  part  of  the  bone  and 
below  and  ijalegstal  to  this  a  tuberosity,  the  bicipital, 
rough  behind  and  smooth  in  front. 

The  lower  extremity  has  two  .>  articular  cavities.  The 
lowest  is  triangular,  base  ^ftwjjrf  c6ncave  in  both  di- 
rections, while  that  on  the  inner  side  is  longest  from 


ANATOMY   FOR   NURSES 

before  bacKward  and  is  a  mere  articular  strip.  The 
lowest  is  the  carpal,  the  inner  the  sigmoid  cavity.  Ex- 
ternally the  bone  terminates  in  a  blunt  point,  the  sty- 
loid  process,  easily  felt  and  an  important  landmark  at 
the  wrist.  The  back  of  the  lower  extremity  is  marked 
by  grooves,  separated  by  ridges,  for  the  passage  of 
tendons. 

The  shaft  is  distinctly  three  sided  with  one  sharp 
border,  the  mtcrnal  or  interosseous,  where  the  mem- 
brane  which  binds  it  to  the  ulna  is  attached.  The 
outer  surface  is  rough  and  convex.  The  anterior  has 
an  oblique  line  across  its  upper  third. 

THE  ULNA 

The  ulna,  the  large  internal  bone,  decreases  in  size 
from  above  downward. 

The  upper  extremity  is  made  up  of  two  processes, 
o^ecranon  above  and  coranoid  below,  which  form,  an- 
teriorly, a  receiving  surface  for  a  trochlea,  the  great 
sigmoid  cavity,  that  is  a  central  ridge  with  a  groove 
on  each  side,  to  fit  the  trochlea  of  the  humerus.  Each 
process  terminates  in  a  point  which  fits  into  the  cor- 
responding fossa  of  the  humerus.  The  back  of  the 
olecranon  is  rough  and  subcutaneous.  The  outer  face 
of  the  coranoid  has  a  small  cavity,  the  lesser  sigmoid, 
continuous  with  the  greater,  for  the  rim  of  the  ra- 
dius. 

The  lower  extremity  consists  of  two  processes.  The 
one  at  the  inner  back  part  is  a  blunt  point,  the  styloid 
process,  which  is  subcutaneous  and  the  most  promi- 
nent landmark  of  the  wrist.  The  outer  elevation,  sep- 


OSTEOLOGY  39 


arated  from  the  styloid  by  a  groove,  is  articular  below 
and  around  its  circumference.  The  rim  fits  into  the 
sigmoid  cavity  of  the  radius,  while  a  cartilage  sepa- 
rates the  lower  face  from  the  carpus. 

The  shaft,  for  its  upper  two  thirds,  is  very  triangular, 
showing  a  prominent  posterior  border,  subcutaneous 
throughout,  a  sharp  thin  external  or  interosseous  and 
an  indistinct  anterior  border.  The  anterior  and  pos- 
terior faces  are  the  best  marked  for  muscular  attach- 
ment. 

THE  PATE 


The  patella  is  a  sesamoid  bone  developed  in  the 
tender  of  the  triceps  exfenlfjf  of  the  leg. 

Its  posterior  surface  corresponds  to  the  anterior  of 
the  olecranon  process  ;  i.  e.,  is  the  receiving  surface  for  a 
trochlea.  The  large  end  of  the  bone  is  above  and  it 
terminates  in  a  blunt  point  below.  The  anterior  face  is 
rough  and  ridged.  The  bone  is  in  fact  the  olecranon 
process  of  the  tibia. 

THE  TIBIA 

The  tibia,  is  the  internal,  and  many  times  the  larger, 
bone  of  the  leg  and  the  only  one  entering  into  the 

knee  joint 


The  upper  extremity  presents  an  inner  and  an  outer 
tuberosity,  the  outer  showing  a  facet  for  the  fibula  and 
the  inner  a  groove  for  a  tendon,  aupportmguic  glciioid  ^-£ 
cavities  for  the  enndyles  of  the  femur.  The  inner  cav- 
ity is  oval  and  deeper  than  the  outer,  which  is  circular. 
Between  the  two  is  a  short,  thick  bifurcated  jywne^  Be- 


40  ANATOMY    FOR    NURSES 

low  the  cavities  in  front  is  the  anterior  tubercle  of  the 
tibia,  rough  below  and  smooth  above. 

The  lower  extremity  is  quadrilateral,  but  is  prolonged 

downward  on  its  anner  face  into  an  irregular  process 

\ .  >  '-  •  -  *  , 

called  the  internal  malleolus,  whose  inner  face  is  rough 

and  subcutaneous  and  forms  an  important  landmark 
of  the  foot  and  ankle — opposite  the  malleolus  there  is 
a  rough  triangular  depression  for  the  fibula.  The 
summit  of  the  bone,  articular  and  concave,  a  little 
wider  in  front  than  behind  is  called  the  tarsal  cavity 
and  receives  the  astragalus. 

The  shaft,  like  that  of  the  ulna  tapers  from  above 
downward  and  is  three  sideid.  Its  anterior  border, 
crest  or  shin,  and  its  tmumal  surface  are  both  sub- 
cutaneous and  much  exposed  to  injury.  The  pos- 
terior face  begins  above  in  a  triangle,  base  up,  the  pop- 
liteal, which  is  marked  off  by  a  ridge  of  the  same 
name.  Below  it  is  narrower  and  less  well  marked. 
This  surface  is  notable  for  carrying  the  largest  of 
the  nutrient  foramina.  The  outer  border  is  interos- 
seous. 

THE  FIBULA 

The  upper  extremity  of  the  fibula  is  nearly  globular, 
presenting  a  round  articular  facet  ittieiiw&iyi  and  a 
rough,  subcutaneous,  nonarticular  knob  externally.  The 
lower  extremity  has  a  pear-shaped  articular  surface,  a 
part  of  the  ankle,  internally  and  externally  the  sub- 
cutaneous rough  face  of  the  (vdcrjwl  inaUcolns,  as  im- 
portant a  landmark  as  the  internal. 

The  shaft,  like  the  entire  bone,  is  very  slender.  It 
fits  opposite  the  tibia  and  is  bound  to  it  at  each  end 


OSTEOLOGY  41 

like  the  pin  to  a  broach.  It  is  so  twisted  that  its  bor- 
ders and  surfaces  change  places  from  above  down- 
ward. Its  chief  function  seems  to  be  to  support  the 
outer  side  of  the  ankle. 


THE  HAND 

The   Carpus,   Metacarpus,   and   Phalanges 

The  carpus  is  made  up  of  eight  irregular  bones  ar- 
ranged in  two  rows,  the  upper  of  Avhich  forms  the 
wrist  joint  while  the  lower  presents  a  set  of  irregular 
articular  facets  for  the  metacarpus:  First  row,  scaph- 
oid, semilunar,  cuneiform,  pisiform ;  second  rowT,  tra- 
pezium, trapezoid,  os  magnum,  unciform.  The  car- 
pus is  convex  and  rough  on  its  dorsal  surface  and  con- 
cave and  rough  on  its  palmar  face.  Above  it  presents 
a  condyle,  long  diameter  from  side  to  side  and  convex 
in  both  directions.  Inferiorly  the  most  external  facet 
is  saddle-shaped  for  the  metacarpal  bone  of  the  thumb 
while  the  facets  for  the  remaining  metacarpal  bones 
are  less  regular  in  outline  and  show  less  freedom  of 
movement, 

The  metacarpus  is  made  up  of  five  long  bones 
known  numerically  from  the  outer  side.  They  vary 
in  appearance,  the  first,  that  of  the  thumb  being  short, 
thick  and  marked  by  a  saddle-shaped  facet  above,  that 
of  the  index  finger,  the  second,  being  the  longest,  the 
third  having  a  styloid  process  at  its  upper  outer  angle, 
the  fourth  none  of  these  appearances,  and  the  fifth 
being  articular  on  only  one  side.  The  lower  or  distal 
extremity  of  each  terminates  in  a  rounded  head  com- 


42  ANATOMY   FOR   NURSES 

pressed  from  side  to  side,  which  is  as  large  as,  or 
larger  than,  the  upper  extremity. 

The  shaft  is  concave  anteriorly  and  laterally  and 
convex  posteriorly. 

The  phalanges  are  fourteen  long  bones  arranged  in 
columns  of  three  for  each  finger  except  the  thumb. 
The  one  which  articulates  with  a  metacarpal  bone  is 
called  a  first  or  proximal  phalanx,  the  next  the  second, 
and  the  last  the  third  or  distal. 

The  upper  extremity  of  a  first  phalanx  has  a  cup- 
like  cavity  for  the  head  of  a  metacarpal  bone. 

The  lower  extremity  shows  a  trochlea.  The  second 
phalanges  would  show  a  receiving  surface  for  a  trochlea 
above  and  a  trochlea  below;  while  the  third  has  a  re- 
ceiving surface  for  a  trochlea  above,  and  below  termi- 
nates in  an  irregular  rough  surface  which  supports  the 
nail  behind  and  the  pulp  of  the  finger  in  front.  The 
shaft  is  convex  posteriorly  and  concave  anteriorly  and 
decreases  in  length  for  each  row. 


THE  FOOT 

The  Tarsus,  Metatarsus,  and  Phalanges 

The  tarsus  consists  of  seven  irregular  bones  arranged 
in  two  rows  from  behind  forward:  os  calcis  and  astra- 
galus in  the  first  row;  scaphoid,  cuboid  and  three,  in- 
ternal, middle  and  external,  cuneiform  bones  in  the 
second. 

The  os  calcis,  or  heel  bone,  longer  than  the  others, 
projects  backward  to  form  a  lever  on  the  bottom  of 
which  the  weight  of  the  body  largely  rests  and  which 
is  used  for  raising  that  weight  in  walking.  Above  it 


OSTEOLOGY  43 

has  two  articular  facets,  separated  by  a  groove,  the 
sulcus  calcanei,  for  the  astragalus.  Below  it  and  on 
each  side  it  is  rough  and  nonarticular,  the  outer  side 
convex,  the  inner  concave  and  the  lower  marked  by 
anterior  and  posterior  tubercles.  In  front  there  is  a 
concavo-convex  articular  surface  for  the  cuboid.  , 

The  astragalus,  a  nearly  square  bone,  has  five  articu- 
lar faces,  three  of  which  are  continuous.  The  upper 
face  is  convex  from  before  backward,  wider  in  front 
than  behind,  continuous  with  the  lateral  articular 
facets  which,  writh  it,  form  a  blunt  wedge  fitting  into 
a  sort  of  mortise  formed  by  the  tibia  and  fibula.  The 
facet  for  the  latter  is  pear-shaped,  large  end  below, 
and  much  larger  than  that  for  the  tibia.  In  front  of 
the  upper  facet  is  a  constricted  neck.  The  anterior  ex- 
tremity is  an  articular  head  for  the  scaphoid.  The 
lower  surface  is  divided  into  a  large,  posterior,  con- 
cave, and  a  small  anterior  convex  facet  for  the  os 
calcis,  separated  by  a  groove  called  sulcus  tali,  which 
forms,  with  the  sulcus  calcanei,  the  sinus  tarsi  when  the 
bones  are  articulated.  The  thin  posterior  extremity  is 
marked  by  an  oblique  groove. 

The  cuboid  is  wedged  in  between  other  bones,  hav- 
ing the  os  calcis  behind,  fourth  and  fifth  metatarsals  in 
front,  and  the  scaphoid  and  external  cuneiform  to 
its  inner  side.  Its  lower  face  has  a  deep  groove  and  a 
prominent  ridge,  both  called  peroneal,  the  outer  end  of 
which  can  be  felt  about  the  middle  of  the  outer  side  of 
the  foot.  Its  upper  surface  is  rough;  its  posterior  sur- 
face projects  partly  under  the  os  calcis.  There  are  two 
articular  surfaces  on  its  anterior  extremity  and  usually 
but  one  on  its  inner  face. 


44  ANATOMY   FOR   NURSES 

The  scaphoid,  supposed  to  be  boat-shaped,  is  con- 
cave posteriorly  for  the  astragalus,  convex  and 
marked  by  three  wedge-shaped  facets  in  front  for  the 
cuneiform  bones,  and  rough  and  convex  on  its  remain- 
ing aspects.  Internally  it  terminates  in  a  blunt  tuber- 
osity,  forming  an  important  landmark  on  the  inner 
face  of  the  foot. 

The  three  cuneiform  bones  are  known  from  within 
outward  as  first,  second,  and  third ;  or  internal,  middle, 
and  external.  They  are  all  wedge-shaped  but  the  first, 
which  is  the  largest  and  less  regularly  so  than  the 
others.  The  first  also  has  its  large  end  downward  while 
the  others  have  the  longest  side  upward.  The  first 
can  be  felt  on  the  inner  side  of  the  foot  and  it  and  the 
other  two  on  top.  Behind  they  all  articulate  with  the 
scaphoid  while  in  front  each  supports  a  metatarsal 
bone,  the  internal  the  first,  the  middle  the  second  and 
the  external  the  third.  All  touch  the  second. 

The  metatarsal  bones,  like  the  metacarpal,  are  five 
in  number  and  are  named  numerically  from  the  inner 
side.  They  resemble  the  similar  bones  of  the  hand 
but  can  be  distinguished  from  them  by  the  facts  that 
the  shafts  taper  from  back  to  front  and  the  head  or 
distal  end  is  much  smaller  than  the  base.  The  first 
metatarsal  is  much  larger  than  the  first  metacarpal  and 
has  a  concave  facet  instead  of  concavo-convex  on  its 
proximal  end. 

The  phalanges  are  also  like  those  of  the  hand  in 
number  and  general  arrangement,  but  differ  from  them 
in  having  shafts  so  short  that  they  form  mere  con- 
necting links  between  the  articular  extremities. 

The  foot,  as  a  whole,  is  concave  on  its  lower  or 


OSTEOLOGY  45 

plantar  aspect  both  from  side  to  side  and  from  before 
backward,  forming  an  arch  which  makes  the  chief 
weight  rest  on  the  posterior  tuberosities  of  the  os  calcis 
and  the  ball  of  the  big  toe. 

THE  HYOID 

The  hyoid  is  a  small  but  most  important  bone  lying 
in  the  neck.  The  base  of  the  tongue,  the  larynx,  and 
pharynx  are  fastened  to  it.  It  is  shaped  something 
like  a  horseshoe,  but  the  toe  or  front  of  the  shoe  is 
thick  and  strong,  forming  the  body  of  the  bone,  while 
the  slender  heels  stick  out  behind  like  horns.  If  the 
neck  is  grasped,  just  above  the  Adam's  apple,  between 
the  thumb  and  index  finger  the  outline  of  the  body 
and  horns  can  be  easily  discerned. 

THE  SKELETON  OF  THE  HEAD 

The  head  is  rather  arbitrarily  divided  into  the  cra- 
nium or  upper  part,  and  the  face,  or  front.  There  is  no 
sharp  line  of  demarcation  between  the  two.  There  are 
eight  bones  in  the  head  and  fourteen  in  the  face.  Those 
of  the  head  are  occipital  at  the  back,  frontal  in  front,  a 
parietal  on  each  side  connecting  the  first  two,  a  tem- 
poral on  each  side  connecting  the  top  and  base  which  is 
formed  by  the  ethmoid  and  sphenoid  with  parts  of  the 
frontal  and  occipital. 

In  the  face  two  superior  maxillary,  two  malar,  two 
nasal  and  one  inferior  maxillary  form  the  visible  bones 
which  can  be  felt  in  the  living  being,  while  a  lachry- 
mal in  each  orbit,  a  palate,  forming  the  back  part  of 
the  nose  and  mouth,. an  inferior  turbinate  in  each  nos- 


46 


ANATOMY   FOR   NURSES 


j.   4. — Front  view  of  skull. 


OSTEOLOGY  47 

tril  and  a  vomer  betAveen  the  nostrils  complete  the 
number. 

The  top  of  the  skull  is  made  up  of  the  frontal,  the 
two  parietal s,  and  part  of  the  occipital.  Where  the 
occipital  and  the  parietals  should  meet,  an  opening  is 
found  in  the  newborn  called  the  posterior  fontanelle 
and  a  similar  space  is  found  at  the  junction  of  the 
parietals  and  frontal,  the  anterior  fontanelle. 

The  face  showTs  the  sloping  frontal  bone  above  and 
below  the  eye  sockets  (orbits)  one  on  each  side  of  the 
projecting  nose,  formed  by  the  nasal  and  nasal  pro- 
cesses of  the  superior  maxillary  bones.  Below  the  nose 
comes  the  opening  of  the  mouth,  containing  thirty-two 
teeth,  if  all  are  present,  whose  roof  is  formed  in  front 
by  the  horizontal  part  of  the  upper  maxilla  and  be- 
hind by  a  similar  process  of  the  palate,  and  front  and 
sides  by  the  lower  jaw  but  whose  floor  is  wanting.  On 
each  side  of  the  nose,  at  a  little  distance  from  it,  is 
the  prominence  formed  by  the  cheek  or  malar  bones, 
leading  along  a  subcutaneous  ridge,  the  zygomatic 
arch,  to  the  temporal  bone  just  in  front  of  the  external 
auditory  meatus,  the  most  important  appearance  on 
the  lateral  aspect  of  the  skull.  A  large  depression  in 
front  of  this  opening  is  the  temporal  fossa.  The  su- 
perior maxilla,  next  to  the  largest  bone  of  the  face,  is 
hollow  and  its  cavity,  the  antrum  of  Highmore,  com- 
municates with  the  nasal  cavity,  so  that  disease  may 
readily  extend  from  nose  to  antrum.  The  nasal  cavity 
has  a  part  of  its  roof  formed  by  a  sieve-like  piece  of 
the  ethmoid,  so  there  is  a  very  thin  wall  between  the 
nose  and  the  brain  cavity.  The  inner  wall  of  each 
nasal  cavity  is  flat  and  formed  chiefly  by  the  vomer. 


48  ANATOMY   FOR   NURSES 

The  outer  wall  has  three  projecting  shelves  of  bone 
(the  turbinates)  striking-  into  it,  so  that  this  wall  is 
very  irregular  and  complex. 

The  orbits  are  two  four  sided  pyramids  laid  flat, 
whose  apices  point  inward  and  backward  and  whose 
nearly  circular  bases  open  on  the  face.  The  apex  of 
each  is  formed  by  the  optic  foramen,  through  which 
the  nerve  of  sight  passes  from  the  cranium  to  the 
orbit.  The  sides  of  the  pyramid  are  known  as  roof, 
floor,  inner  and  outer  walls.  The  inner  wall  is  made  of 
very  thin  bone  separating  the  orbit  from  the  nasal 
cavity  and  skull,  with  both  of  which  it  communicates. 
The  opening  into  the  nose  is  the  canal  for  the  nasal 
duct,  by  which  the  excess  of  tears  is  carried  into  the 
nose  to  moisten  respired  air. 

The  inferior  maxilla  is  the  only  bone  of  the  face 
with  articular  surfaces.  It  is  U-shaped  and  turned  up 
at  the  back  to  form  two  rami  which  terminate  in  a 
condyle  behind,  and  a  coronoid  process,  for  muscular 
attachment,  in  front.  The  body  has  sockets  for  sixteen 
teeth. 

If  the  top  of  the  skull  be  sawed  off  so  as  to  expose 
the  interior,  the  under  surface  of  the  vertex,  or  upper 
wall,  and  the  upper  surface  of  the  base  can  be  seen. 
The  interior  of  the  skull  is  marked  by  numerous  fur- 
rows spreading,  like  limbs,  chiefly  from  a  hole  in  the 
sphenoid  by  which  the  chief  artery  for  the  skull  and 
its  membranes  enters.  There  are,  besides,  broader  but 
shallower  depressions,  separated  by  slight  ridges,  which 
lodge  the  convolution  and  sulci  of  the  brain.  A  large 
straight  groove  runs  from  the  front  to  a  projection 
called  anterior  occipital  protuberance  at  the  back, 


-10 

[—11 
-12 


Fig.  5. — Base  of  skull,  upper  surface.  1,  Anterior  fossa;  2,  Middle  fossa; 
3,  Posterior  fossa;  4,  Cribriform  plate;  5,  Ootic  foramen;  6,  Foramen 
rotundum;  7,  Mid.  lacerated  foramen  and  carotid  canal;  8,  Foramen  spino- 
sum;  9,  Internal  auditory  meatus;  10,  Eminence  of  semicircular  canal; 
11,  Jugular  foramen;  12,  Foramen  magnum. 


50 


ANATOMY   FOR   NURSES 


1 


Fig.  6. — Base  of  skull,  lower  surface. 


OSTEOLOGY  51 

which  lodges  a  chief  element  in  the  venous  circulation. 
This  is  joined  at  right  angles  on  the  occipital  bone  by 
similar  and  deeper  grooves.  These  lodge  what  are 
called  the  longitudinal  and  lateral  sinuses. 

The  upper  surface  of  the  base  of  the  skull  is  divided 
into  three  spaces,  each  lower  than  the  preceding,  known 
as  anterior,  middle  and  posterior  fossae  of  the  skull. 
The  anterior  is  formed  mainly  by  the  horizontal  part  of 
the  frontal  and  the  ethmoid,  the  middle  by  the  body 
and  great  wings  of  the  sphenoid  and  the  temporal,  while 
the  posterior  is  chiefly  formed  by  the  occipital,  but  has 
contributions  from  the  temporal.  Each  fossa  lodges  a 
corresponding  part  of  the  brain  and  each  has  openings 
through  which  the  cranial  nerves  find  exit  from,  and 
blood  vessels  entrance  to,  the  skull.  In  the  midde  fossa 
a  bulge  on  the  petrous  part  of  the  temporal  shows  the 
proximity  of  the  ear  to  the  brain,  from  which  it  is  sepa- 
rated by  a  thin  shell  of  bone.  The  anterior  fossa 
shows  openings  for  the  first  nerve  and  the  optic  fora- 
men for  the  second.  The  middle  fossa  has  the  anterior 
lacerated  foramen  and  the  foramen  rotundum;  the  pos- 
terior, the  foramen  magnum  and  the  jugular  foramen. 

The  lower  surface  of  the  base  shows  the  roof  of  the 
mouth,  ending  in  the  hard  palate  behind,  just  above 
which  are  the  posterior  nares.  Behind  this  is  the  basilar 
process  of  the  occipital  and,  behind  that,  the  foramen 
magnum  with  a  condyle  on  either  side.  Laterally  are 
seen  the  foramen  ovale,  the  opening  for  the  entrance  of 
the  carotid  artery  and  the  jugular  foramen  for  the  trans- 
mission of  numerous  nerves  and  the  jugular  vein. 


CHAPTER  III 
ARTHROLOGY 

Arthrology  is  the  study  of  the  joints,  more  par- 
ticularly of  those  which  are  movable. 

When  bones  are  united  by  interlocking  processes  of 
bone,  as  in  the  skull,  the  joint  is  called  a  synartkrosis. 
These  are  immovable  joints. 

When  the  union  is  by  fibrous  tissue  separating  the 
bones  and  permitting  movement  only  by  twisting  the 
fibers,  it  is  called  amphiarthrosis  or  slightly  movable 
joints,  as  between  the  bodies  of  the  vertebrae. 

When  two  smooth  articular  surfaces  are  bound  to- 
gether by  ligaments,  usually  exterior  to  the  joint,  it  is  a 
diarthrosis  or  freely  movable  joint.  Every  joint  belongs 
to  one  of  the  three  classes.  Synarthrodial  joints  are  con- 
fined to  the  skull;  amphiarthrodial  to  the  vertebral  col- 
umn, pelvis,  hand,  and  foot.  The  other  joints  are  diar- 
throdial. 

DIARTHRODIAL  ARTICULATIONS 

Of  these  there  are  six  varieties: 

Arthrodial,  formed  by  flat  surfaces  with  very  slight 
motion  often  in  many  directions.  Example:  That  be- 
tween articular  processes  of  vertebrae. 

Ginglymoid,  hinge  or  trochlear,  where  motion  occurs 
freely  but  in  only  two  directions.  Example:  Elbow, 
knee. 

Condyloid,  formed  by  a  condyle  and  a  proper  receiv- 

52 


ARTHROLOGY  53 

ing  cavity.  Example:  Wrist,  occipital  condyles,  and 
cavities  of  atlas. 

Saddle-shaped,  or  concavo-convex,  or  joints  by  recipro- 
cal reception.  Example:  Sternoclavicular. 

Pivot,  or  trochoid,  when  one  bone  revolves  around 
another.  Example:  There  are  but  two,  atloaxoid  and 
radioulnar. 

Ball  and  socket,  or  enarthrodial,  when  a  cup-like  cav- 
ity receives  a  rounded  head.  Example:  There  are  but 
two,  shoulder  and  hip. 

The  movements  of  which  joints  are  capable  appear 
innumerable,  but  are  really  limited  to  eight. 

Gliding,  most  marked  in  arthrodial  joints,  where  it  is 
the  only  movement,  but  present  in  all  diarthrodia. 

Flexion,  movement  usually  forward  but  sometimes 
backward. 

Extension,  the  reverse  of  flexion. 

Abduction,  movement  away  from  a  midline,  usually 
that  of  the  body. 

Adduction,  movement  toward  a  midline. 

These  are  called  the  four  angular  movements  and 
when  performed  in  succession,  in  any  order,  produce 
the  sixth  movement  called 

Circumduction,  which  may  be  inward  or  outward. 

Revolution,  where  one  bone  revolves  around  another. 
It  occurs  only  in  pivot  joints. 

Rotation  occurs  only  at  the  shoulder  and  hip  and  is 
made  by  turning  the  arm  or  thigh  inward  or  outward 
around  an  axis  drawn  from  the  center  of  the  head  of  the 
bone  to  the  internal  tuberosity  at  the  lower  end. 


54  ANATOMY   FOR   NURSES 

ARTICULATIONS  OF  THE  VERTEBRAL  COLUMN 

The  vertebrae  articulate  by  their  bodies  and  articular 
processes  and  have  ligaments  binding  other  parts  which 
do  not  touch.  The  joint  between  the  bodies  is  an  am- 
phiarthrosis  effected  by  a  disk  of  fibrocartilage  which 
performs  the  triple  function  of  binding  the  bones  to- 
gether, lengthening  the  column  and  furnishing  a  cush- 
ion between  each  pair  of  bones  to  lessen  shock.  Move- 
ment can  take  place  by  twisting  the  fibers,  or  by  com- 
pressing the  disk  on  one  side  while  it  is  stretched  on 
the  other.  Running  the  length  of  the  column  both  on 
the  front  and  back  of  the  bodies  is  a  b.undl?  of  fibers 
forming  the  anterior  and  posterior  oSiSmen  ligaments  of 
the  spine.  That  on  the  front  is  the  stronger.  That  on 
the  back  runs  in  the  spinal  canal.  Ligaments  are  also 
found  between  spines  and  attached  to  their  points, 
called  interspinous  and  supraspinous.  Capsular  liga- 
ments surround  the  articular  processes. 

As  the  atlas  has  no  body,  there  is  no  intervertebral 
disk  between  the  first  and  second  cervical  vertebras.  A 
very  strong  band  is  attached  to  the  inner  face  of  each 
lateral  mass  and  encircles  the  odontoid  process,  forming 
the  transverse  ligament.  Capsular  ligaments  surround 
the  articular  processes  and  a  continuation  of  the  anterior 
common  ligament  passes  to  a  tubercle  on  the  front  of  the 
atlas. 

The  odontoid  process  has  a  diverging  bundle  running 
from  near  its  summit  to  the  margin  of  the  foramen  mag- 
num on  each  side.  These  are  the  check  ligaments  because 
they  prevent  too  much  turning  of  the  head.  A  part  of 
the  posterior  comiAon  ligament  extends  from  the  body 


ARTHROLOGY  55 

of  the  axis  over  the  odontoid  process  to  the  anterior 
margin  of  the  foramen  magnum. 

The  atlas  is  held  to  the  occipital  bone  by  capsular 
ligaments  around  the  anterior  processes,  by  thin  mem- 
branes running  from  the  anterior  and  posterior  arches 
to  the  corresponding  margins  of  the  foramen  magnum 
and  by  a  continuation  of  the  anterior  common  from  the 
tubercle  of  the  atlas  to  the  occipital  in  front  of  the  fora- 
men magnum. 

Throughout  the  column  the  numerous  and  powerful 
muscles  of  the  back  are  powerful  means  of  binding  the 
bones  together. 

The  ligaments  binding  the  last  lumbar  vertebra  to  the 
sacrum  are  practically  identical  with  those  between  the 
lumbar  vertebrae. 

A  capsular  ligament  is  a  bag  made  of  white  fibrous 
tissue  whose  top  and  bottom  are  formed  by  the  opposed 
articular  surfaces  of  the  bones.  The  latter  are  covered 
by  encrusting  cartilage  and  the  whole  is  lined  by  a 
synovial  membrane  furnishing  the  fluid  which  lubricates 
the  joint.  All  synovial  membranes  are  protected  by 
more  or  less  complete  capsules ;  but  the  fibers  in  some 
joints  are  so  much  thicker  in  some  parts  than  in  others, 
that  they  are  spoken  of  as  if  they  were  separate  liga- 
ments, though  always  blended  with  the  capsule. 

Movements. — The  head  rocks  backward  and  forward 
on  the  condyles  which  move  in  the  receiving  cavities  of 
the  atlas.  There  is  some  lateral  movement  also.  Move- 
ment forward  is  flexion,  backward,  extension.  At  the 
atloaxoid  joints,  the  atlas  alone  moves.  It  revolves  to 
either  side  around  the  odontoid  process,  the  articular 


56  ANATOMY   FOR   NURSES 

process  of  the  side  to  which  movement  is  made  gliding 
backward,  and  the  other  forward. 

Bending  the  body  forward  is  flexion;  backward  exten- 
sion; to  either  side,  right  or  left  lateral  flexion.  In 
forward  movement  the  front  of  the  intervertebral  disks 
is  compressed  and  the  supraspinous  and  interspinous 
ligaments  stretched,  the  inferior  articular  process  of 
each  vertebra  gliding  upward.  The  reverse  takes  place 
in  extension.  The  corresponding  mechanism  would 
produce  lateral  movement.  The  performance  of  each  of 
these  movements  in  succession  would  be  circumduction. 

COSTOVERTEBRAL  ARTICULATIONS 

The  ribs  are  held  to  the  vertebral  column  by  a  three 
pronged  bundle  running  to  each  of  the  vertebrae  with 
which  the  rib  articulates,  and  to  the  intervertebral  disk, 
from  the  front  of  the  head;  by  a  small  band  between 
the  ridge  on  the  head  of  the  rib  and  the  intervertebral 
disks ;  by  capsular  ligaments  surrounding  the  articular 
facets;  and  by  strong  fibers  running  from  the  back  of 
the  neck  of  the  ribs  to  the  front  of  the  transverse  pro- 
cesses and  capsular  ligaments  surrounding  these  articu- 
lar facets. 

Movements. — The  lower  anterior  end  of  the  ribs  moves 
upward,  revolving  on  an  axis  formed  by  the  transverse 
processes.  This  thrusts  the  sternum  forward  and  in- 
creases the  diameters  of  the  chest. 

ARTICULATIONS  OF  THE  CLAVICLE 

The  clavicle  articulates  with  the  sternum  by  a  sad- 
dle-shaped joint.  An  inter  articular  plate  of  cartilage  is 


ARTHROLOGY  57 

interposed  between  the  bones,  attached  at  the  top  of  the 
clavicle  and  at  the  bottom  of  the  receiving  cavity.  A 
capsule  surrounds  the  joint.  A  strong  bundle  extends 
from  the  cartilage  of  the  first  rib  to  the  rhomboid  im- 
pression of  the  clavicle. 

The  clavicle  articulates  with  the  acromion  process 
of  the  scapula  by  an  arthrodial  joint.  Sometimes  there 
is  a  cartilage  between  the  bones  and  a  capsule  always 
binds  them  together.  This  is  a  very  poor  security,  so  the 
joint  is  reinforced  by  powerful  fibers  which  run  upward 
from  the  coracoid  process  where  the  clavicle  crosses  it 
to  the  under  surface  of  that  bone.  These  fibers  are  de- 
scribed as  the  conoid  and  trapezoid  ligaments  because  the 
shape  is  different.  Viewed  from  behind  they  form  a  cone, 
from  in  front,  a  trapezium. 

Movements. — The  clavicle  can  move  freely  in  any  di- 
rection at  either  end,  though  the  range  of  movement  is 
limited.  At  the  inner  end  the  least  degree  of  move- 
ment is  upward,  as  in  lowering  the  shoulder.  In  all 
movements  the  shoulder  is  carried  in  a  direction  op- 
posite that  in  which  the  head  of  the  clavicle  moves.  At 
the  outer  end  the  scapula  is  the  more  movable  bone. 

THE  ENARTHRODIAL  JOINTS 

These  are  but  two,  the  shoulder  and  hip.  In  each 
the  receiving  cavity  is  deepened  by  a  fibrocartilage  sur- 
rounding the  margin  of  the  cavity  and  called  the  glenoid 
ligament,  but  the  glenoid  ligament  of  the  hip  is  the 
stronger  and  deeper  and  has  to  bridge  the  gap  at  the 
lower  inner  acetabular  rim.  Each  has,  as  almost  its 
only  ligament,  a  strong  capsule  thickened  at  certain 


58  ANATOMY   FOR    NURSES 

points ;  but  the  capsule  of  the  shoulder  is  long  and  per- 
mits a  wide  separation  of  the  bones,  while  that  at  the 
hip  holds  the  femur  in  close  contact  with  its  cavity. 

The  capsule  at  the  shoulder  is  attached  around  the 
anatomical  neck  of  the  humerus;  that  of  the  hip  is 
fastened  just  internal  to  the  trochanters,  so  that  all  the 
neck  of  the  femur  is  in  the  cavity  of  the  joint.  The 
strengthening  bands  of  the  shoulder  are  unimportant; 
one  of  those  at  the  hip,  the  Y  ligament,  having  its  tail 
fastened  to  the  inferior  anterior  spine  of  the  ilium  and 
its  spreading  limbs  to  the  anterior  intertrochanteric 
line,  is,  surgically,  of  the  highest  importance.  A  round 
bundle,  ligamentum  teres,  running  from  the  head  of  the 
femur  to  the  bottom  of  the  acetabulum  is  peculiar  to  the 
hip.  Each  joint  has  an  extensive  synovial  membrane 
which,  as  elsewhere,  lines  the  interior  of  the  capsule  as 
well  as  covers  the  bones.  Each  is  greatly  strengthened 
and  protected  by  surrounding  muscles;  but  the  shoulder 
is  more  dependent  upon  this  "ligamentous  action  of 
muscles"  than  the  hip.  Each  possesses  great  number 
and  range  of  movements,  though  the  range  is  much 
greater  at  the  shoulder ;  and  in  each  the  movements  can 
be  described  in  nearly  identical  words. 

Movements. — Flexion  in  both  cases  is  movement  for- 
ward. At  the  shoulder  the  head  of  the  humerus  spins 
around  an  axis  drawn  from  the  great  tuberosity  through 
the  center  of  the  head ;  at  the  hip  the  axis  is  drawn  from 
the  great  trochanter.  Extension  is  the  reverse  of  flexion. 
Abduction  is  movement  of  the  arm  or  thigh  away  from 
the  midline  of  the  body,  the  head  gliding  down  in  either 
case,  pressing  on  the  inferior  fibers  of  the  capsule  liga- 
ment, rupturing  it  and  being  dislocated  if  exaggerated. 


ARTHROLOGY  59 

Adduction  is  the  reverse.  Circumduction  is  the  succes- 
sive performance  of  these  four  angular  movements.  Axial 
rotation,  performed  at  these  two  joints  alone,  is  move- 
ment,  inward  or  outward,  causing  the  whole  bone  to  spin 
around  an  axis  drawn  from  the  center  of  the  head  to  the 
inner  tuberosity,  or  condyle. 

THE  GINGLYMOID  OR  HINGE  JOINT 

The  chief  hinge  joints  are  the  elbow,  knee,  ankle,  and 
interphalangeal.  They  are  so  dissimilar  that  separate 
descriptions  of  each  must  be  given. 

The  radius  and  ulna  both  enter,  with  the  humerus, 
into  the  elbow  joint.  These  bones  of  the  forearm  are 
held  together  above  by  an  encircling  ligament,  the  orbic- 
ular, attached  at  each  end  of  the  lesser  sigmoid  cavity 
and  binding  the  radius  firmly  to  the  ulna.  Below  an- 
terior and  posterior  fibers  extend  between  the  two  bones 
and  a  triangular  cartilage,  attached  by  its  base  be- 
tween the  two  articular  cavities  and  by  its  apex  to  a 
pit  between  the  two  processes  of  the  ulna,  at  £nce  binds 
these  bones  together  and  cuts  the  ulna  out  of  the  wrist 
joint.  The  shafts  are  bound  together  by  a  thin  but  strong 
membrane  attached  to  their  interosseous  ridges.  This 
firm  binding  of  the  two  bones  together  keeps  the  radius 
from  independent  action  at  the  elbow.  In  revolving 
around  the  ulna  it  spins  on  the  humerus,  but  it  must 
follow  the  ulna  in  movement  of  the  elbow  joint. 

The  chief  ligaments  concerned  in  the  elbow  joint  are 
the  internal  and  external  lateral.  The  first  is  the  strong- 
est. It  is  attached  by  its  apex  to  the  inner  condyle  and 
by  its  base  to  the  olecranon  and  coronoid  processes 


60  ANATOMY   FOR   NURSES 

where  they  form  the  margins  of  the  great  sigmoid  cav- 
ity. The  external  is  fastened  above  to  the  outer  eondyle 
and  below  to  the  orbicular  ligament,  not  touching  the 
radius  as  it  would  interfere  with  it  in  revolution.  The 
anterior  and  posterior  are  hardly  more  than  fibers  of 
the  capsular  ligament,  the  work  of  these  ligaments  be- 
ing performed  by  muscles.  The  synovial  membrane 
lines  the  superior  radioulnar  joint  as  well  as  the  elboAv. 
Movements. — Flexion,  movement  forward,  and  exten- 
sion are  the  only  movements.  The  joint  is  not  a  straight 
line,  owing  to  the  greater  length  of  the  inner  ridge  of 
the  trochlea,  and  the  movements  are  not  straight.  In 
extension  the  foramen  is  carried  away  from  the  midline 
making  an  angle  open  outward. 

The  knee  joint  is  the  largest  and  most  complex  in  the 
body.  The  condyles  of  the  femur  rest  on  the  glenoid 
cavities  of  the  tibia  and  are  bound  to  it  by  ligaments 
both  inside  and  outside  the  joint,  and  the  patella  plays 
on  the  trochlea  connecting  the  condyles.  The  cavities 
of  the  tibia  are  deepened  by  glenoid  ligaments,  but 
these  rest  on  the  tibia  without  being  directly  attached 
to  it  and,  consequently,  participate  in  the  movements 
and  accidents  of  the  joint. 

The  interior  ligaments,  called  crucial,  are  two  in  num- 
ber and  are  attached,  the  anterior  in  front  of  the  spine 
and  to  the  outer  side  of  the  condyloid  notch,  the  posterior 
behind  the  spine  and  to  the  inner  side  of  the  same  notch. 

The  external  lateral  is  fastened  to  the  outer  tuberosity 
above  and  below,  in  two  bundles,  to  the  styloid  process 
and  head  of  the  fibula. 

The  internal  lateral,  broader  and  somewhat  triangular, 
seizes  the  inner  tuberosity  of  the  femur  above  and  below 


ARTHROLOGY  61 

spreads  out  over  the  inner  tuberosity  and  upper  part 
of  the  shaft  of  the  tibia. 

The  patella  is  enveloped,  except  on  its  posterior  face, 
in  the  tendon  of  the  great  extensor  of  the  leg.  The 
lower  part  of  this  tendon  runs  from  the  lower  end  of  the 
patella  to  the  lower  part  of  the  anterior  tubercle  of  the 
tibia,  supplying  the  place  of  an  anterior  ligament.  It 
is  called  ligamentum  patellae. 

The  nnstwjflr  Ugmme/nt  is,  in  the  main,  the  expanded 
tendon  of  the  semimembranous  muscles,  inserted  into  the 
tibia  below  and  passing  upward  to  seize  the  femur  be- 
tween and  above  the  condyles. 

The  synovial  membrane  is  very  extensive,  lining  the 
interior  of  all  the  ligaments  except  the  crucial  which  it 
covers  and  excludes  from  the  synovial  cavity,  running 
under  the  glenoid  ligaments  and  communicating  with 
bursae  around  the  joint.  Bursae  are  svnovial  sacs,  like 
water  bags,  placed  under  many  tendons  around  joints. 
They  are  very  numerous  around  the  shoulder,  knee  and 
hip.  They  contain  synovia.  Some  do  not  communicate 
with  joints  and  contain  mucus. 

Movements. — Movement  backward  is  flexion.  The  leg 
is  carried  upward  against  the  thigh,  the  glenoid  cavities 
moving  backward  on  the  condyles  and  the  patella  glid- 
ing downward  on  the  trochlea.  The  reverse  is  exten- 
sion. The  greater  length  of  the  internal  condyles  causes 
some  rotation  in  these  movements,  inward  in  flexion, 
outward  in  extension. 

The  ankle  is  a  peculiar  form  of  hinge.  The  oblong 
hole  a  carpenter  makes  to  receive  a  suitable  projection 
of  timber  is  called  a  mortise.  The  projection  is  called 
a  tenon.  In  this  joint  the  tibia  and  fibula  furnish  the 


62  ANATOMY   FOR    NURSES 


mortise,  the  astragalus,  the  tenon;  both  are  wider  in 
front  than  behind. 

The  internal  lateral  or  deltoid  ligament  is  a  thick 
strong  bundle  attached  above  to  the  inner  malleolus  and 
below,  by  its  base,  to  the  astragalus,  os  cacis  and  scaph- 
oid. It  binds  these  bones  of  the  foot  together  in  ad- 
dition to  being  the  strongest  ligament  of  the  ankle. 

The  external  lateral,  arising  from  the  outer  malleolus, 
splits  into  three  fasciculi,  or  bundles,  which  are  attached 
in  front  to  the  aotragalus,  in  the  middle  to  the  oo-  oaleis 
and  behind  to  the  aslxagalus.£*j£  d4/r4///A-~ 

The  anterior  and  posterior  are  nearly  negligible  as 
ligaments,  but  the  place  of  a  posterior  is  supplied  by  the 
great  extensor  of  the  foot,  called  tendo  Achilles.  A  syno- 
via! membrane  lines  all  the  structures. 

Movement.  —  Flexion  brings  the  back  of  the  foot  up 
toward  the  leg  and  forces  the  tenon  backward  in  the 
mortise.  Extension  is  the  reverse,  pointing  the  toes 

downward  and,  by  bringing  the  narrowest  part  of  the 
k  '  •  • 
ton<5a  into  the  broadest  part  of  the  mortise,  allows  slight 

lateral  play  and  places  the  joint  at  great  disadvantage  as 
to  sprains. 

THE  CONDYLOID  ARTICULATIONS 

The  joints  of  this  variety  are  the  wrist,  temporo- 
maxillary,  occipito-atloid  and  metacarpo-phalangeal. 

The  condyle  of  the  wrist  is  furnished  by  these  bones 
of  the  first  row  of  the  carpus,  scaphoid,  semilunar  and 
cuneiform;  the  cavity  by  the  lower  end  of  the  radius 
and  the  cartilage  which  cuts  the  ulna  out  of  the  joint. 

Ligaments  called  anterior,  posterior,  internal  and 
external  lateral  unite  with  each  other  to  form  a  capsule 


ARTHROLOGY  63 

and  are  attached  to  the  radius  chiefly  above  and  the 
first  row  of  the  carpus  below. 

Movements. — Condyloid  joints  have  all  movements  ex- 
cept axial  rotation.  In  every  movement  the  condyle 
glides  in  a  direction  opposite  that  taken  by  the  part 
moved ;  i.  e.,  if  the  hand  moves  inward  the  condyle  moves 
outward,  etc. 

The  temporo-maxillary  joint  is  a  condyle  on  each  side 
and  a  glenoid  cavity  formed  on  the  squamous  part  of  the 
temporal  bone.  An  interarticular  cartilage  lies  between 
the  bones  and  moves  with  the  coiidyles.  A  capsular 
ligament  strengthened  particularly  on  the  outer  side, 
where  it  is  called  the  external  lateral  ligament,  binds  the 
bones  together.  Some  bundles  of  cervical  fascia  are  also 
classed  as  ligaments. 

Movements. — The  jaw  moves  upward  in  crushing  food, 
downward  in  opening  the  mouth,  and  alternately  to  each 
side  in  grinding  food.  In  the  latter  movement  the  con- 
dyles  glide  alternately  backward  and  forward;  i.  e.,  if 
the  jaw  is  trust  to  the  left,  that  condyle  goes  backward 
and  the  right  forward. 

In  the  metacarpo-  and  metatarso-phalangeal  joints 
the  long  diameter  is  from  before  backward  while  the 
receiving  cavity  is  almost  circular.  The  chief  liga- 
mentous  action  is  exerted  by  the  extensor-tendons  on  the 
back  and  a  fibrocartilaginous  mass  connected  with  the 
flexor  tendons  on  the  front.  This  is  true  also  of  the  in- 
terphalangeal  joints  of  both  hand -and  foot.  These  are 
trochlear  or  hinge  articulations. 

Movements. — At  the  metacarpo-  and  metatarso-phalan- 
geal joints  some  lateral  movement  is  permitted,  particu- 
larly at  the  joints  on  the  free  (i.  e.  outer  and  inner)  sides 


64  ANATOMY    FOR    NURSES 

of  the  hand  and  foot.  The  interphalangeal  joints  can 
perform  only  flexion  and  extension.  Flexion  is  forward 
in  the  hand  and  downward  in  the  foot. 

The  intercarpal  and  carpo-metacarpal  joints  are  ar- 
throdia  bound  together  by  dorsal  and  palmar  ligaments 
and,  on  the  free  borders,  by  lateral  ligaments  as  well. 
This  is  not  true  of  the  metacarpal  bone  of  the  thumb  and 
the  trapezium,  which  is  a  saddle-shaped  joint  with  a  cap- 
sular  ligament. 

The  intertarsal  joints  are  much  larger  than  the  in- 
tercarpal. The  astragalus  and  os  calcis  are  mainly 
bound  together  by  fibers  filling  the  sinus  tarsi  and 
form  the  first  row  of  the  tarsus.  The  second  row  is  held 
together  by  dorsal  and  plantar  ligaments  and  is  held 
to  the  first  by  very  strong  plantar  ligaments  which  pass 
from  the  os  calcis  to  the  cuboid  and  the  scaphoid.  These 
ligaments  are  very  important  in  maintaining  the  arch  of 
the  foot. 

The  tarso-metatarsal  joints  are  so  similar  to  the  cor- 
responding joints  of  the  hand  that  no  separate  descrip- 
tion is  needed. 

PELVIC  LIGAMENTS 

The  pubic  bones  are  bound  together  by  a  plate  of 
fibrocartilage  between  their  inner  ends  and  by  liga- 
ments above,  below,  behind,  and  in  front.  The  sacrum 
is  united  to  the  ilia  by  anterior  and  posterior  fibers,  of 
which  the  latter  are  much  the  more  powerful.  A  very 
large  bundle  is  attached  to  the  side  of  the  sacrum  and 
coccyx  by  one  end  and  splits  to  seize  the  spine  and  tu- 
berosity  of  the  ischium  at  the  other,  closing  the  deep 


ARTHROLOGY 


65 


Fig.  7. — Pelvic  ligaments  and  capsule  of  hip. 


66  ANATOMY    FOR   NURSES 

gap  between  sacrum  and  ischium  and  converting  the 
sciatic  notches  into  the  sciatic  foramina,  greater  and 
lesser. 

A  membrane  called  the  triangular  ligament  fills  the 
space  between  the  ischio-pubic  rami  while  a  similar 
membrane,  the  thyroid,  fills  all  but  the  top  of  that 
foramen. 


CHAPTER  IV 
MYOLOGY 

Muscles  are  striated  or  nonstriated.  In  the  study  of 
myology  only  the  striated  are  considered. 

Muscles  lie  beneath  the  skin  and  superficial  fascia  in 
all  parts  of  the  body  and  beneath  a  special  membrane 
called  the  deep  or  investing  fascia  in  some  parts.  These 
fascias  are  studied  with  the  muscles.  The  superficial 
fascia  lies  just  beneath  the  skin,  which  it  enables  to  move 
freely,  and  carries  the  greater  part  of  the  body  fat  and 
the  superficial  blood  vessels  and  nerves.  As  it  has  no 
bony  attachments,  it  permits  collections  of  fluid  or  air 
to  spread  widely  through  or  beneath  its  meshes.  The 
deep  fascias,  most  pronounced  in  the  neck  and  upper 
and  lower  extremities,  seek  attachment  to  bone  at  every 
opportunity,  and  hence  limit  the  spread  of  any  accumu- 
lation beneath  them.  They  also  send  down  septa  be- 
tween muscles  and  groups  of  muscles,  by  which  the  area 
for  muscular  attachment  is  greatly  increased  without 
adding  to  the  weight  of  the  body,  as  a  corresponding 
increase  of  bone  would. 

Muscles  are  sometimes  spread  out  in  broad  sheets, 
but  are  more  frequently  gathered  into  large  bundles  of 
varying  shape  and  direction.  As  their  function  is  to 
produce  movement  of  some  sort,  they  run  over  mov- 
able joints  and  are  fastened  on  either  side  of  one  or 
more  such  joints.  These  attachments  are  spoken  of  as 
the  origin  and  insertion,  the  least  movable  point  usually 
being  the  origin.  These  attachments  take  place  through 

67 


68  ANATOMY  FOR   NURSES 

long  or  short  masses  of  white  fibrous  tissue  called  ten- 
dons. Sometimes  the  tendinous  fibers  are  imperceptible 
to  the  unaided  eye,  when  the  attachment  is  said  to  be 
fleshy;  in  other  cases  some  tendinous  fibers  can  be  seen 
and  this  is  called  a  nnisculo-tcmlinous  attachment.  In 
still  other  cases  the  tendon  is  spread  out  in  a  thin  sheet 
when  it  is  called  an  aponeurosis. . 

Muscular  nomenclature  is  very  difficult,  because  there 
are  so  many  muscles  and  the  names  have  been  derived 
from  such  a  variety  of  sources.  Those  producing  an- 
gular movements  are  flexors,  extensors,  abductors  and 
adductors.  Others  are  named  from  the  direction  of 
their  fibers,  shape,  from  points  of  attachment,  etc. 

As  the  physiologist  seldom  pays  attention  to  the  action 
of  individual  muscles,  the  anatomist  spends  an  unusual 
amount  of  time  on  this  subject.  Muscles  act  very  much 
as  a  stretched  piece  of  rubber  does;  that  is,  by  getting 
shorter  and  thicker.  If  a  movable  joint  is  between  the 
attachments,  such  shortening  will  bring  the  two  bones 
nearer  together;  or,  if  a  cavity  is  beneath  the  muscle, 
and  the  bones  do  not  move,  the  size  of  the  cavity  will 
be  diminished.  If,  thereiore,  the  points  of  attachment 
are  given  and  the  joints  are  known,  the  chief  function 
of  a  muscle  may  be  inferred. 

It  makes  little  difference  at  what  point  the  study 
of  the  muscular  system  is  begun.  In  actual  practice  it 
is  convenient  to  begin  with  the  abdominal  wall  because 
one  can  sooner  see  and  study  the  abdominal  viscera. 

THE  ABDOMINAL  MUSCLES 

This  group  consists  of  three  pairs  of  broad  and  two 
of  smaller  muscles.  The  broad,  and  one  pair  of  slender, 


MYOLOGY 


69 


Fig.  8. — Muscles.     Front  of  neck.,  trunk,  and  upper  extremity. 


70  ANATOMY    FOR   NURSES 

muscles  are  named  from  the  direction  of  their  fibers — 
two  oblique,  one  transverse,  and  one  straight.  The  re- 
maining pair  receive  their  name  from  their  shape — 
pyramidal. 

The  oblique  muscles  are  external  and  internal  and  be- 
neath them  is  the  transverse.  The  fibers  of  the  external 
oblique  run  downward  and  inward;  of  the  internal 
oblique,  upward  and  inward,  and  those  of  the  transver- 
salis  run  around  the  body,  from  behind  forward.  It 
is  evident  that  this  arrangement  makes  a  net  wrork  of 
fibers  around  the  abdomen  so  that,  when  the  muscles 
shorten,  or  contract,  pressure  is  made  on  the  contents  of 
the  abdomen  in  various  directions. 

The  external  oblique  arises  from  the  eight  lower 
ribs  and  is  inserted  into  the  crest  of  the  ilium  and 
spine  of  the  os  pubis.  The  part  of  the  tendon  stretching 
from  the  anterior  superior  spine  of  the  ilium  to  the 
pubis  is  called  Poupart's  ligament  and  is  free  between 
its  points  of  attachment.  The  remaining  fibers  are  in- 
serted into  the  linea  alba.  This  is  a  thickened  mass  of 
fibers  stretching  from  the  ensiform  cartilage  to  the  sym- 
physis  pubis  made  up  of  fibers  from  all  the  broad  mus- 
cles of  the  abdomen. 

The  internal  oblique  is  attached  below  to  the  outer 
part  of  Poupart's  ligament  and  the  crest  of  the  ilium. 
Above  it  seizes  the  four  lower  ribs  and  the  whole  length 
of  the  linea  alba  and  the  crest  of  the  pubis. 

The  transversalis  rises  from  the  outer  half  of  Pou- 
part's  ligament,  the  crest  of  the  ilium,  the  spines  of  the 
lumbar  vertebrae  and  from  the  inner  faces  of  the  six 
lower  ribs,  and  is  inserted  into  the  linea  alba  and  the 
crest  of  the  pubis, 


MYOLOGY  71 


The  recti  are  flat  muscles  arising  from  the  front  of 
the  symphysis  pubis  and  its  crest  and  inserted  into  the 
fifth,  sixth,  and  seventh  ribs  beside  the  sternum.  These 
muscles  lie  on  either  side  of  the  linea  alba  and  are  en- 
closed in  a  sheath  furnished  by  the  aponeuroses  of  the 
broad  muscles. 

The  pyramidalis  lies  in  the  sheath  of  the  rectus,  is 
sometimes  wanting  and  rather  unimportant. 

Opposite  the  spine  of  the  pubis  there  is  a  hole  in  the 
aponeurosis  of  the  external  oblique  which  transmits  the 
round  ligament  in  the  feniale  and  the  sperniatic_cprd  in 
the  male.  It  is  called  the  superficial  abdominal  ring. 

The  abdominal  wall  is  thus  seen  to  consist  of  skin, 
superficial  fascia  which  contains  much  fat,  the  external 
oblique,  internal  oblique,  transversalis,  a  delicate  fascia 
like  the  superficial,  and  a  sort  of  internal  skin  called 
the  peritoneum. 

Action.  —  By  contracting,  these  muscles  decrease  the 
size  of  the  abdominal  cavity,  compressing  its  contents 
and  expelling  parts  of  them  through  the  openings  pro- 
vided for  the  purpose  —  urethra,  rectum  and  vagina. 
They  can  also  bend  the  body  on  the  pelvis  or  the  pelvis 
on  the  body. 

The  diaphragm,  the  great  respiratory  muscle,  is  a  thin 
dome,  when  in  position,  though  shaped  like  a  palm- 
leaf  fan  when  cut  out  and  spread  flat,  separating  the 
thoracic  from  the  abdominal  cavity.  The  floor  of  the 
thorax  is,  therefore,  convex  and  the  roof  of  the  abdo- 
men concave. 

The  muscle  springs  from  the  inner  faces  of  the  six 
lower  ribs,  where  it  interlocks  with  the  transversalis, 
and  by  two  long  tendons,  which  leave  a  space  between 


72  ANATOMY   FOR    NURSES 

them  for  the  abdominal  aorta,  from  the  bodies  of  the 
lumbar  vertebrae.  Between  the  last  rib  and  the  side  of 
the  spine  two  tendinous  arches,  called  ligamenta  arcu- 
ata  interna  and  externa,  give  origin  to  fibers  which  fill 
in  what  would  otherwise  be  a  gap  in  the  muscle. 

The  insertion  is  into  a  central  tendon,  shaped  some- 
thing like  a  clover  leaf,  and  called  trefoil.  It  follows 
that  the  fibers  proceed  in  different  directions.  Those 
from  the  ribs  are  directed  upward  and  inward,  those 
from  the  vertebras,  upward  and  forward,  all  convex 
upward  and  outward  or  backward. 

The  diaphragm  allows  structures  to  pass  from  the 
thorax  to  the  abdomen  either  through  or  behind  it. 
The  aorta  passes  with  the  thoracic  duct  and  other 
structures  through  the  aortic  opening  which  is  behind. 
The  opening  for  the  esophagus  is  above  and  in  front  of 
the  aortic  and  that  for  the  inferior  vena  cava  is  in  the 
central  tendon  and  still  higher  up. 

Action. — If  the.  ribs  are  fixed  when  the  diaphragm 
contracts,  the  whole  muscle  is  pulled  downward. 
At  the  same  time  the  curved  fibers  become  straight, 
leaving  a  greater  interval  between  them  and  the  ribs. 
All  this  increases  the  size  of  the  thorax.  The  muscle  is 
the  great  agent  of  inspiration. 

THORACIC  MUSCLES 

Two  muscles,  pectoralis  major  and  minor,  occupy  the 
front  of  the  chest ;  the  serratus  magnus,  the  sides ;  and 
the  intercostals,  the  spaces  between  the  ribs.  Except 
the  latter,  these  are  as  much  muscle  of  the  upper  ex- 
tremity as  of  the  trunk. 


MYOLOGY  73 

The  pectoralis  major  occupies  the  front  of  the  ster- 
num, a  part  of  the  clavicle  and  five  of  the  ribs.  It  is 
inserted  into  the  outer  bicipital  ridge  of  the  humerus. 

The  pectoralis  minor  springs  from  the  third,  fourth 
and  fifth  ribs  and  is  inserted  into  the  coracoid  process 
of  the  scapula. 

CXv\J\AA-i^/v 

The  serratus  magnus-  springs  from  the  eight  upper 
ribs  and,  running  between  the  scapula  and  the  thorax, 
is  inserted  into  the  posterior  border  of  the  scapula. 

Action. — They  all  tend  to  draw  the  upper  extremity 
toward  the  midline,  i.  e.,  they  are  adductors,  or  act 
from  their  insertion.  They  tend  to  draw  the  ribs  apart 
and  expand  the  chest. 

MUSCLES  OF  THE  CERVICAL  REGION 

Except  the  platysma,  these  muscles  are  enclosed  in 
a  deep  or  investing  fascia,  the  cervical,  which  fastened 
to  the  spines  of  the  vertebrae  behind,  runs  around  the 
entire  neck  like  a  high  stock,  and  is  fastened  behind 
where  it  started.  Above,  it  is  fastened  to  the  lower 
jaw,  and  below,  to  the  clavicle  and  to  structures  in  the 
thorax.  It  not  only  binds  everything  in  the  neck  in 
an  envelope,  but  sends  off  partitions  which  form 
sheaths  for  muscles  and  blood  vessels. 

The  platysma  myoides  is  a  thin  muscle  spreading 
over  the  sides  of  the  neck  beneath  the  superficial  and 
above  the  deep  fascia.  Deeper  than  this  muscle,  in  a 
sheath  of  the  deep  fascia,  lies  one  of  the  most  important 
muscles  of  the  body,  sterno-cleido-mastoid  whose  name 
indicates  its  attachment.  It  arises  from  the  clavicle  and 
sternum  and,  running  upward 'and  backward  across  the 


74  ANATOMY   FOR    NURSES 

side  of  the  neck,  is  inserted  into  the  mastoid  process  of 
the  temporal  and  the  occipital  bones.  It  can  be  felt 
throughout  its  course, 

Action. — The  two  bow  the  head,  or  either,  acting  alons, 
can  pull  the  head  toward  the  shoulder  and  turn  the 
face  to  the  opposite  side. 

The  hyoid  bone  separates  the  next  layer  into  two 
groups  distinguished  as  suprakyoid,  or  elevators,  and 
infrahyoid,  or  depressors  of  the  hyoid  bone. 

Two  of  the  depressors,  sterno-hyoid  and  sterno-thy- 
roid,  spring  from  the  back  of  the  sternum  and  are  in- 
serted into  the  body  of  the  hyoid  and  wing  of  the  thy- 
roid cartilage  respectively.  A  short  muscle  called 
thyro-hyoid  continues  the  latter  to  the  hyoid. 

The  omo-hyoid  runs  nearly  inward  from  the  upper 
border  of  the  scapula,  forms  a  central  tendon  which 
plays  through  a  loop  of  fascia  which  binds  it  to  the 
first  rib,  then  turns  nearly  upward  to  reach  the  hyoid. 

Two  of  the  elevators  of  the  hyoid,  genio-  and  mylo- 
hyoid,  are  attached  to  the  lower  jaw  and  the  hyoid 
bone ;  one  the  digastric,  is  double  bellied  and  is  pulled 
down  to  the  hyoid  by  a  loop  of  fascia,  being  fastened  at 
one  end  to  the  temporal  bone  and  the  other  to  the 
lower  jaw.  The  stylo-hyoid  may  be  omitted.  The 
niylo-  and  genio-hyoids  aid  in  forming  the  floor  of  the 
mouth. 

Action. — These  muscles  can  either  elevate  the  hyoid 
bone  or  depress  the  lower  jaw. 

A  deeper  group,  of  which  the  scaleni  and  recti  are  the 
most  prominent,  are  flexors,  anteriorly  or  laterally,  of 
the  vertebral  column,  or,  like  the  scaleni,  elevators  of 
the  upper  ribs  and  inspiratory  agents. 


MYOLOGY  75 

MUSCLES  OF  THE  HEAD  AND  FACE 

The  muscles  of  expression  are  a  group  of  small  mus- 
cles usually  attached  to  bone  at  one  end  and  the  skin 
of  the  face  at  the  other.  Their  contraction  causes  a 
change  of  expression. 

Among  the  important  muscles  of  this  region  are  the 
muscles  of  mastication  used  in  chewing  the  food. 

The  temporal  muscle  occupies  the  fossa  of  the  same 
name  and  is,  like  it,  fan-shaped.  Below  it  grasps  the 
coronoid  process  of  the  lower  jaw. 

The  masseter  is  attached  to  the  zygomatic  arch  above 
and  the  ramus  of  the  jaw  below. 

The  pterygoids,  internal  and  external,  are  attached 
to  the  base  of  the  skull  and  below,  to  the  lower  jaw, 
the  inner  seizing  the  ramus,  and  the  outer,  the  neck  of 
the  condyle. 

There  is  a  thin  flat  muscle  in  the  cheek,  the  buccina- 
tor which  is  classed  with  the  masticators  because  it 
holds  the  food  between  the  teeth.  Its  paralysis  causes 
the  food  to  bulge  out  the  cheek. 

Action. — All  but  the  external  pterygoid  are  elevators 
of  the  jaw  and  hence  crushers  of  food.  The  outer 
pterygoid  causes  lateral  motion  and  protrusion  for- 
ward. It  is  a  grinder  of  food. 

ORBITAL  GROUP 

The  eyeball  is  moved  in  its  socket  by  four  muscles 
called  recti  and  two  called  oblique.  The  recti  are 
superior,  inferior,  internal  and  external.  They  are  ar- 
ranged around  the  eyeball  as  their  names  indicate  and 


76 


ANATOMY   FOR   NURSES 


MYOLOGY  77 

each  pulls  so  as  to  turn  the  eye  upward,  downward, 
inward  or  outward.  All  but  one  of  the  muscles  of  the 
eyeball  rise  from  the  corresponding  margin  of  the  optic 
foramen  and  are  insered  into  the  outer  (sclerotic)  coat 
of  the  eye. 

The  superior  oblique  rises  from  the  margin  of  the 
optic  foramen,  passes  through  a  pulley  at  the  upper  in- 
ner part  of  the  eye  and  its  tendon  then  runs  downward 
and  outward  to  the  sclerotic. 

The  inferior  oblique  rises  from  the  upper  jaw,  within 
the  orbit,  and  passes  outward,  beneath  the  eyeball  to 
reach  the  same  coat  on  its  outer  side.  Hence  it  revolves 
the  eye  outward,  while  the  superior  revolves  it  inward. 

The  elevator  of  the  upper  lid  (levator  palpebrae 
superioris)  also  lies  in  the  orbit,  rising  from  the  margin 
of  the  optic  foramen  and  being  inserted  into  the  upper 
tarsal  cartilage. 

MUSCLES  OF  THE  BACK 

The  superficial  fascia  of  the  back,  thick  and  rather 
coarse,  is  continuous  with  that  of  the  axilla,  abdomen, 
neck,  and  buttock.  Beneath  it  is  a  broad  expanse  of 
aponeurotic  fibers,  forming  the  vertebral  aponeurosis 
and  giving  attachment  to  many  muscles.  The  muscles 
of  this  region  are  arranged  in  layers  from  behind  for- 
ward. The  first  layer  is  made  up  of  two  muscles,  the 
trapezius  above  and  latissimus  dor  si  below.  The  two  ex- 
tend from  the  back  of  the  occiput  to  the  sacrum. 

The  trapezius  (the  two  together  are  diamond-shaped) 
arises  from  the  occiput  and  cervical  and  dorsal  spines 
and  is  inserted  into  the  spine  of  the  scapula  and  the 
outer  third  of  the  clavicle. 


78 


ANATOMY   FOB    NURSES 


Fig.  10. — Muscles.     Back  of  trunk,  upper  extremity,  and  hips. 


MYOLOGY  79 

The  latissimus  dorsi  stpts,  underneath  the  trapezius, 
from  about  the  sixth  dorsal  spine,  and  rises  from  the 
dorsal  and  lumbar  spines,  the  back  of  the  sacrum,  the 
posterior  third  of  the  ilium  and  three  or  four  of  the 
lower  ribs.  Its  tendon  passes  over  the  lower  angle  of 
the  scapula  and  is  inserted  into  the  inner  bicipital  ridge 
of  the  humerus. 

Action. — The  trapezius  draws  the  scapulas  together  and 
elevates  them.  The  latissimus  draws  the  humerus  down- 
ward and  backward. 

The  muscles  of  the  next  layer  are  the  rhomboid,  which 
is  attached  to  the  lower  cervical  and  upper  do™? a1. 
spines  and  the  peste^r  border  of  the  scapula ;  and  the 
levator  anguli  scapulae  which  rises  from  the  upper  cer- 
vical transverse  processes  and  is  inserted  into  the  up- 
per angle  of  the  scapula.  It  draws  the  scapula  upward 
and  inward  while  the  rhomboid  draws  it  inward. 

A  large  mass  of  muscular  and  tendinous  fibers  fills 
the  sacral  groove  and  the  space  on  either  side  of  the 
vertebrae  column.  It  is  called  erector  spinae  and  is  con- 
tinued by  a  succession  of  alternate  origins  and  inser- 
tions up  to  the  skull.  It  maintains  the  body  in  the 
erect  posture  and  can  restore  it  to  that  position  after 
flexion. 

MUSCLES  OF  THE  UPPER  EXTREMITY 

Scapular  group 

There  are  five  muscles  in  this  group  largely  con- 
cerned in  rotation  of  the  humerus.  Three  are  named 
from  the  scapular  fossae  from  which  they  arise  while 
the  other  two  spring  from  the  axillary  border  and  are 
called  teres  (round)  muscles  from  their  shape. 


80  ANATOMY   FOR   NURSES 

The  subscapularis  arises  from  the  fossa  of  that  name 
on  the  front  of  the  scapula  and  is  inserted  into  the 
small  tuberosity  of  the  humerus.  It  is  an  inward  ro- 
tator. 

The  supraspinatus  arises  from  the  supraspinous  fossa ; 
the  infraspinatus,  from  the  infraspinons  fossa;  the 
teres  minor,  from  the  axillary  border  of  the  scapula; 
and  are  inserted  in  the  order  given,  into  three  impres- 
sions on  the  great  tuberosity.  The  last  two  are  out- 
ward rotators ;  the  first  an  abductor  of  the  humerus. 

The  teres  major  rises  from  the  lower  part  of  the  axil- 
lary border  of  the  scapula  and  is  inserted  with  the  latis- 
simus  dorsi  into  the  inner  bicipital  ridge.  It  acts  with 
that  muscle  and  is  an  inward  rotator. 

The  rounded  outline  of  the  shoulder  is  largely  due  to 
a  bulky  muscle  called  deltoid.  It  covers  the  joint  in 
every  aspect  except  below  and  internally.  It  is  at- 
tached above  to  the  spine  and  acromion  of  the  scapula 
and  the  outer  third  of  the  clavicle.  Below  it  seizes  the 
outer  face  of  the  humerus  about  half  way  down. 

The  humeral  group  is  made  up  of  three  muscles  in 
front  and  one  behind.  They  are  enclosed  in  a  strong 
fibrous  envelope  which  encircles  the  arm  and  blends 
with  a  strong  fascia  covering  the  axillary  space  and 
pectoral  muscles.  Below  this  fascia  seizes  the  condyles 
of  the  humerus  and  is  continued  over  the  muscles  of  the 
forearm,  forming  a  special  thickening  on  the  front  and 
back  of  the  wrist  called  anterior  and  posterior  annular 
ligaments.  It  is  then  continued  into  the  hand  ,-is  ihc 
palmar  fascia. 

The  triceps  (three  heads)  is  on  the  back  of  the  hu- 
merus. Its  long  or  middle  head  rises  from  the  scapula 


MYOLOGY  81 

and  the  other  two  from  the  back  of  the  humerus.  All 
are  inserted  into  the  olecranoii  process. 

The  biceps  (two  heads)  rises  from  the  coracoid  proc- 
ess and  margin  of  the  glenoid  cavity  of  the  scapula  and 
is  inserted  into  the  bicipital  tuberosity  of  the  radius.  It 
and  the  triceps  pass  over  two  joints.  An  offshoot  from 
the  inner  head  is  called  the  coraco-brachialis  and  is  in- 
serted into  the  inner  face  of  the  humerus. 

The  brachialis  a&tie«fr  springs  from  the  lower  half  of 
the  front  of  the  humerus  and  is  inserted  into  the 


'TV 


Action.  —  The  triceps  extends  the  forearm;  the  biceps 
and  brachialis  antious  flex  it,  and  the  biceps  is  a  su- 
pinator.  The  coraco-brachialis  is  an  adductor  and 
flexor  of  the  arm. 

- 

The  muscles  of  the  forearm  are  arranged  in  anterior    . 
and  posterior  groups,  and  each  of  these  in  two  layerar, 
All  muscles  on  the  front  are  either  flexors  or  pronat&rs; 
and  all  on  the  back  are  either  extensors  or  supinaiors^J  ^ 

On  the  front  a  great  mass  composed  of  five  muscles 
springs  from  the  inner  coiidyle  of  the  humerus.  As  this 
mass  passes  downward,  it  gives  off  first  a  round  muscle, 
the  pronator  radii  teres  which  is  inserted  into  the  mid- 
dle of  the  radius;  a  slender  tendon,  the  flexor  carpi 
radialis,  inserted  into  the  metacarpal  bone  of  the  index 
finger;  a  still  smaller  tendon,  the  palmaris  longus  in- 
serted into  the  palmar  fascia;  a  group  of  four  tendons 
seizing  the  middle  phalanx  of  each  of  the  four  fingers; 
and  a  more  muscular  tendon  which  is  fastened  to  the 
metacarpal  bone  of  the  little  finger.  These  are  the 
flexor  sublimis  digit  orum  and  the  flexor  carpi  ulnaris. 

Beneath  these  are  three  muscles,  the  flexor  longus 


82  ANATOMY   FOR   NURSES 

pollicis  rising  from  the  radius  and  inserted  into  the  last 
phalanx  of  the  thumb;  the  flexor  profundus  digitorum, 
arising  from  the  ulna  and  inserted  into  the  last  phalan- 
ges of  the  fingers ;  and  the  pronator  quadratus  spring- 
ing from  the  lower  fourth  of  the  ulna  and  seizing  the 
same  amount  of  the  radius. 

Action. — Pronation  is  revolving  the  radius,  carrying 
the  hand  so  as  to  turn  the  palm  backward,  and  supina- 
tion  is  the  reverse.  As  movement  forward  is  flexion  in 
this  extremity,  the  flexors  have  their  function  indicated 
by  their  names.  Thus  the  flexor  carpi  radialis  flexes 
the  wrist  but  draws  it  to  the  radial  side;  the  uliiaris 
pulls  to  the  ulnar  side,  while  the  digital  flexors  are  dis- 
tinguished as  superficial  (sublimis)  and  deep  (profun- 
dus)  and  act  on  the  phalanges  into  which  they  are  in- 
serted. After  flexing  the  fingers,  they  can  act  on  the 
joints  above. 

On  the  back  of  the  forearm  the  superficial  muscles 
rise  from  the  external  condyle  and  branch  into  a  short 
radial  extensor  (extensor  carpi  radialis  longior),  a  com- 
mon extensor  of  the  fingers  (eommtinls  digitorum),  an 
an  extensor  of  the  little  finger  (Extensor  minimi  di-giti) 
and  an  ulnar  extensor  (Extensor  carpi  ulnaris).  Ex- 
tensors of  the  fingers  are  attached  to  the  whole  length 
of  the  back  of  the  phalanges,  furnishing  posterior  liga- 
ments of  the  joints  as  they  pass  over  them.  The  short 
radial  extensor  is  attached  to  the  metacarpal  bone  of 
the  middle  finger,  and  the  ulnar,  to  that  of  the  little 
finger. 

The  deep  group  comprises  five  muscles.  The  first  of 
these,  the  supinator  -bre^fe  runs  from  the  ulna  around 
the  upper  extremity  of  the  radius,  which  it  seizes.  The 


MYOLOGY  83 

next  three  are  attached  to  one  or  both  bones  of  the  fore- 
arm above  and,  in  consecutive  order  from  above  down- 
ward, to  the  metacarpal  bone,  first  and  second  phalan- 
ges of  the  thumb.  The  last  is  attached  above  to  the 
ulna  and  below  to  the  index  finger  like  all  extensor 
tendons. 

Two  muscles,  brachio-radialis  and  long  radial  exten- 
sor (Extensor  carpi  radialis  longlor),  are  attached  above 
to  the  ridge  above  the  outer  condyle  and  below  the 
first  to  the  styloid  process  of  the  radius  and  the  second 
to  the  metacarpal  bone  of  the  index  finger. 

The  palm  of  the  hand  is  covered  by  a  very  dense 
fascia  which  is  attached  to  the  skin  and  prevents  its 
freedom  of  movement.  This  fascia  is  much  thicker  cen- 
trally than  on  either  side,  where  it  covers  two  groups 
of  muscles,  the  thenar  at  the  base  of  the  thumb  and  the 
hypothenar  at  that  of  the  little  finger. 

The  thenar  muscles  either  flex  the  first  phalanx  of  the 
thumb,  or  draw  the  thumb  to  or  away  from  the  middle 
of  the  hand,  or  approach  the  thumb  to  the  little  finger. 
Hence  the  muscles  rise  from  near  the  middle  of  the 
hand. 

The  hypothenar  group  perform  similar  functions  for 
the  little  finger,  but  their  origin  is  close  to  the  inner 
side  of  the  hand.  Certain  small  muscles  called  interossei 
and  lumbricales  occupy  the  middle  of  the  palm."" 

MUSCLES  OF  THE  LOWER  EXTREMITY 

The  fascia  of  the  lower  extremity  envelopes  that  part 
in  a  way  similar  to  that  found  in  the  upper  extremity. 
It  covers  the  region  of  the  hip,  seizing  not  only  the  crest 


84  ANATOMY   FOR   NURSES 

of  the  ilium  and  the  os  pubis  but  Poupart's  ligament  as 
well.  In  the  thigh  it  is  called  facia  lata.  Descending 
to  the  knee  it  forms  a  strong  roof  for  the  popliteal  space, 
back  of  the  knee  joint,  seizes  the  .tuberosities  of  the  tibia 
and  head  of  the  fibula  and  descends  the  leg,  enveloping 
the  muscles  and  sending  septa  between  them,  as  it  does  in 
the  upper  extremity  and  thigh,  forms  an  anterior  and 
two  lateral  annular  ligaments,  and  ends  by  becoming 
more  or  less  continuous  with  the  plantar  fascia. 

Here  the  muscles  of  the  hip  correspond  to  those  of 
the  shoulder;  those  of  the  thigh,  to  the  arm;  of  the  leg, 
to  the  forearm;  and  of  the  foot,  to  the  hand. 


GLUTEAL  GROUP 

The  hip  muscles  form  a  group  of  nine,  arranged  in 
three  layers,  all  having  their  origin  from  the  innomi- 
nate and  all  inserted  into  some  part  of  the  upper  end 
of  the  femur.  These  are  called  gluteal  and  are  distin- 
guished as  greater,  middle,  and  least,  (maximus,  medius 
and  minimus).  Besides  being  concerned  in  rotation,  like 
the  shoulder  or  scapular  group,  some  of  these  muscles 
have  the  important  function  of  sustaining  the  body  in  the 
erect  posture  by  steadying  the  pelvis  on  the  femur  and 
preventing  the  falling  over  which  would  occur  were  they 
paralyzed.  The  three  gluteal  muscles  are  engaged  in 
this  way.  They  are  found  occupying  all  the  outer  sur- 
face of  the  ilium  and  its  crest  above  and  below  and  are 
inserted  either  into  or  near  the  great  trochanter.  Of  the 
remaining  muscles  of  this  group  two,  obturators  internus 
and  externus,  spring  from  the  obturator  membrane;  a 
third,  the  pyriformis  with  the  obturator  internus,  rises 


MYOLOGY  85 

within  the  pelvis  and  all  are  inserted  into  or  near  the 
pit  on  the  inner  face  of  the  great  trochanter.  All,  except 
the  gluteus  minimus,  which  rotates  inward,  are  outward 
rotators  of  the  femur. 

The  muscles  of  the  thigh  are  arranged  in  anterior, 
posterior  and  internal  groups.  On  the  front  of  the 
thigh  the  muscles  are  either  flexors  of  the  thigh  on 
the  pelvis  or  extensors  of  the  leg  on  the  thigh.  The 
posterior  muscles  are  all  flexors  of  the  leg  and  the 
internal  adductors  of  the  thigh. 

There  are  really  but  two  muscles  on  the  front, 
though  they  are  usually  described  as  five  and  some- 
times seven. 

The-Jbiceps.- flexo^-^emoris  has  a  long  head  called 
psoas  magmis,  which  springs  from  the  lumbar  verte- 
bra?, and  a  short,  the  iliacus  inter nus,  springing  from 
the  iliac  fossa.  It  passesTunder  Poupart's  ligament  and 
is  inserted  into  the  lesser  trochanter. 

The  triceps  extensor  cmris  rises  from  just  above 
the  acetabulum  by  a  long  middle  head  called  rectus;  a 
short  external  called  vast  us  smcrnus^  springs  from  .the. 
outer  part  of  the  femur  and  a  shorter,  vastus  infonvus, 
from  the  inner  and  front  part  of  that  bone.  They 
unite  to  form  a  strong  tendon  which  encloses  the  pa- 
tella and  is  inserted  into  the  anterior  tubercle  of  the 
tibia,  forming  the  anterior  ligament  of  the  knee  joint. 
The  internal  and  external  intermuscular  septa  give  at- 
tachment to  the  two  shorter  heads. 

The  adductor,  or  internal  group,  has  four  heads  called 
pectineus  and  adductors  longus,  brevis,  and  magnus. 
Their  points  of  origin  can  be  separated  but  the  insertion 
can  not.  They  spring  from  the  pectineal  triangle  and 


86  ANATOMY  FOR   NURSES 

outer  face  of  the  os  pubis,  and  from  the  tuberosity  and 
ramus  of  the  ischium.  They  all  run  outward  and 
downward  and  are  inserted  into  linea  aspera. 

Inclosed  between  layers  of  the  fascia  lata  are  three 
thin  muscles,  on  the  outer,  inner,  and  anterior  aspects 
of  the  thigh,  named  tensor  vaginae  femoris,  sartorius 
and  gracilis.  The  first  rises  from  just  back  of,  and  the 
second  from  the  anterior  superior  spine  of,  the  ilium, 
and  the  last  from  the  margin  of  the  pubic  symphysis. 
The  tensor  is  inserted  into  the  fascia  lata  about  half- 
way down.  The  sartorius  and  gracilis,  along  with  the 
semitendinosus,  blend  together  to  form  what  is  called 
the  " goose  foot"  insertion  into  the  inner  face  of  the 
tibia  just  below  the  tuberosity.  The  gracilis  runs 
straight  downward,  the  sartorius  obliquely  downward 
and  inward  at  first  and  then  straight  downward.  Its 
course  is  important  because  of  its  relation  to  the  fem- 
oral artery.  The  tensor's  action  is  indicated  by  its 
name.  The  gracilis  is  an  adductor  of  the  leg  and 
thigh;  the  sartorius  draws  one  leg  across  the  other. 

In  the  posterior  region  there  are  three  muscles, 
biceps  fUxo^Li^u^is  semitendinosus  and  semimembra- 
nosus.  All  of  them  spring  from  the  tuberosity  of  the 
ischium. 

The  semitendinosus  and  long  head  of  the  biceps  rise 
in  common  and  pass  down  the  thigh  to  below  its  mid- 
dle, where  the  short  head  of  the  biceps,  which  rises 
from  the  outer  lip  of  the  linea  aspera,  joins  the  long 
and  the  two  muscles  diverge  to  form  the  upper  boun- 
daries of  the  popliteal  space.  The  biceps  is  inserted 
into  the  head  of  the  fibula  while  the  semitendinosus 
goes  to  the  "goose  foot"  insertion. 


MYOLOGY  87 

The  semimembranosus  lies  a  little  in  front  of  the~ 
other  two  but  also  rises  from  the  tuberosity  of  the 
ischium.  It  passes  to  the  inner  side  of  the  popliteal 
space  and  is  mainly  inserted  into  the  groove  on  the 
inner  tuberosity  of  the  tibia,  but  a  large  part  goes 
into  the  posterior  ligament  of  the  knee  joint. 

Action. — They  all  flex  the  leg  on  the  thigh.  In  stand- 
ing and  walking  they  act  from  below,  pulling  on  the  tu- 
berosity of  the  ischium,  preventing  the  tendency  to 
fall  forward.  They  aid  in  restoring  the  body  to  the 
erect  posture  after  bending  forward  at  the  hips. 

TWTO  layers  of  muscles,  superficial  and  deep,  are 
found  on  the  back  of  the  leg  and  one  each  on  the 
front  and  outer  side. 

The  superficial  layer  at  the  back  is  the  triceps  surae 
whose  heads  are  the  gastrocnemius,  plantaris  and  soleus. 
The  gastrocnemius  rises  from  the  two  condyles  of  the 
femur,  its  outer  head  springing  with  the  plantaris. 
The  two  heads  form  the  lower  boundaries  of  the  popli- 
teal space. 

The  soleus  rises  from  the  tibia  and  fibula  for  several 
inches.  The  three  form  the  strongest  tendon  in  the 
body,  tendo  Achilles,  which  is  inserted  into  the  lower 
part  of  the  posterior  tuberosity  of  the  os  calcis. 

Action. — By  pulling  the  calcis  upward,  it  turns  the 
toes  downward.  This  raises  the  body  on  tiptoes;  i.  e., 
it  is  an  extensor  of  the  foot. 

The  deep  group  contains  the  popliteus,  tibialis  posti- 
cus,  flexor  longus  digit  orum  and  flexor  long  us  hallucis. 

The  popliteus  rises  from  the  outer  tuberosity  of  the 
femur  and  is  inserted  into  the  popliteal  triangle  of  the 
tibia. 


88  ANATOMY   FOR    NURSES 


The  tibialis  pe&tiotts  rises  mainly  from  the  iiiteros- 
seous  membrane,  but  from  tibia  and  fibula  as  well.  Its 
tendon  lies  on  the  concave  inner  face  of  the  calcis  to 
reach  the  tuberosity  of  the  scaphoid  and  inner  cunei- 
form. 

The  flexor  longus  hallucis  rises  from  the  fibula  and  is 
inserted  into  the  last  phalanx  of  the  big  toe.  It  is 
much  larger  than  the  flexor  of  the  toes. 

The  flexor  longus  digitomm  springs  from  the  tibia 
and  is  inserted  into  the  last  phalanx  of  the  four  outer 
toes,  i.  e.,  corresponds  to  the  flexor  profundus  in  the 
upper  extremity.  The  names  explain  the  action  ex- 
cept of  the  tibialis,  which  is  an  extensor  of  the  foot. 

The  anterior  muscles  are  the  tibialis  anticus,  extensor 
longus  dig  it  or  um  find  extensor  proprius  hallucis. 

The  tibialis  ca*Sictts  rises  from  the  tuberosity  and  up- 
per half  of  the  outer  face  of  the  tibia  and  is  inserted 
into  the  inner  cuneiform  and  metatarsal  bone  of  the 
big  toe.  It  flexes  the  foot  and  turns  it  inward;  i.  e., 
inverts  it. 

The  extensor  longus  digitomm  rises  from  the  head 
and  nearly  the  whole  of  the  fibula  and  is  inserted  into 
the  backs  of  the  phalanges  of  the  four  outer  toes  and 
into  the  metatarsal  bone  of  the  little  toe. 

The  extensor  jM^eprius  hallucis  rises  from  the  middle 
two-fourths  of  the  fibula  and  is  inserted  into  the  last 
phalanx  of  tiie  big  toe. 

The  &ut£ifgroup  comprise  the  peroneus  longus  and 
brevis.  They  occupy  the  whole  of  the  outer  aspect  of 
the  fibula  and,  becoming  tendinous,  the  brevis  is  in- 
serted into  the  metatarsal  bone  of  the  little  toe,  the 
longus  into  that  of  the  big  toe,  having  passed  across 


MYOLOGY  89 

the  sole  of  the  foot  through  the  peroneal  groove  on 
the  cuboid. 

All  of  the  last  five  muscles,  except  the  proprius  hallu- 
cis,  spring  from  the  investing  fascia. 

The  peronei  extend  and  evert  the  foot ;  i.  e.,  turn  it  so 
it  rests  on  the  inner  side. 

The  plantar  fascia  is  much  stronger  than  the  palmar, 
but,  like  that,  the  middle  division  is  the  strongest.  It 
covers,  and  gives  origin  to,  three  muscles  which  abduct 
the  great  and  little  toes  and  flex  the  four  outer  toes. 
These  muscles  all  spring  from  the  under  surface  of 
the  calcis,  as  well  as  the  fascia.  Above  them  in  the 
sole  lie  other  layers  of  muscles  which  are  not  im- 
portant. 

The  only  muscle  on  the  dorsum  of  the  foot  is  the 
extensor  brevis  digitorum.  It  rises  from  the  upper 
and  outer  part  of  the  os  calcis  and,  dividing  into  four 
tendons,  is  inserted  into  the  first  phalanx  of  the  big 
toe  and  the  whole  length  of  the  backs  of  the  next 
three  like  all  extensor  tendons. 

The  flexor  tendons  of  the  phalanges  in  both  upper 
and  lower  extremities  are  bound  to  the  bones,  before 
insertion,  in  canals  formed  partly  of  bone,  but  on  three 
sides  by  very  tough  fibrous  tissue  called  thecce.  These 
canals  are  lined  by  synovial  membranes  like  joints. 
The  extensor  tendons  of  the  phalanges  all  furnish 
posterior  ligaments  for  the  joints  over  which  they 
pass. 


CHAPTER  V 

SPLANCHNOLOGT 

The  alimentary  canal  begins  at  the  mouth  and  termi- 
nates at  the  anus.  It  consists  of  the  mouth,  pharynx, 
esophagus,  stomach,  small  and  large  intestines.  The 
pharynx  succeeds  the  mouth  and  lies  in  the  neck. 
The  esophagus  is  in  the  lower  neck  and  thorax  while 
the  digestive  tract  lies  in  the  abdomen. 

The  mouth  presents  thirty-two  teeth  set  in  the  gums 
of  the  upper  and  lower  jaws  and  described  as  four  in- 
cisor, or  cutting,  teeth;  two  canine,  or  tearing;  four 
premolar  and  six  molar,  or  grinding  teeth,  in  each 
jaw.  These  are  the  permanent  teeth.  The  milk  or 
deciduous  teeth  are  twenty  in  number:  four  incisor,  two 
canine,  and  four  molar  teeth  in  each  jaw.  Children 
begin  to  cut  the  teeth  about  the  sixth  month  and  the 
process  continues  up  to  about  the  thirtieth  month.  The 
order  of  eruption  is  the  lower  central  incisors,  upper  in- 
cisors, lower  lateral  incisors  and  first  molars,  canines 
and  second  molars,  each  successive  group  appearing 
from  two  to  six  months  after  its  predecessor. 

The  mouth  is  lined  by  mucous  membrane,  which 
covers  the  tongue  as  well  as  the  cheeks.  On  the  cheeks 
are  the  openings  of  the  ducts  from  the  parotid  salivary 
gland  while  those  of  the  smaller  submaxillary  and  sub- 
lingual  open  together  beneath  the  tongue. 

The  posterior  opening  of  the  mouth  (oral  cavity) 
called  fauces,  is  a  narrow  opening  leading  into  the  ex- 

90 


SPLANCHNOLOGY  91 

panded  pharynx.    The  sides  of  the  fauces  are  boundecT 
by  the  tonsils  (amygdalae)  so  often  the  subject  of  dis- 
ease or  the  object  of  surgery. 

The  upper  part  of  the  succeeding  cavity  is  the 
nasopharynx  and  receives  not  only  the  posterior  nares, 
but  the  openings  of  the  eustachian  tubes,  by  which 
air  is  carried  into  the  middle  ear.  The  oropkarynx  is 
that  part  into  which  the  mouth  opens.  Below  the 
pharynx  contracts  to  the  esophagus  immediately  in  front 
of  which  lies  the  larynx.  The  pharynx  is,  therefore,  the 
space  through  which  food  is  carried  to  the  esophagus 
and  in  which  the  mouth,  nose,  ear  and  voice  box  com- 
municate. Its  walls  are  partly  formed  by  three  mus- 
cles, called  constrictors,  so  arranged  that  they  overlap 
from  below  upward  and  each  can  grasp  and  force  on- 
ward a  morsel  of  food  before  it  escapes  the  one  above. 

The  esophagus  begins  at  the  cricoid  cartilage,  and 
terminates,  opposite  the  tenth  or  eleventh  thoracic 
vertebra,  in  the  stomach.  Its  muscular  wall  is  made 
up  of  longitudinal  and  circular  muscular  fibers  which 
run  around  the  organ  or  throughout  its  length  with  no 
attachments  beyond.  In  the  neck  and  thorax  the  esoph- 
agus is  closely  related  to  important  structures,  es- 
pecially the  great  blood  vessels.  It  lies  directly  be- 
hind the  larynx  and  trachea,  the  speaking  and  breath- 
ing tubes. 

THE  ABDOMEN  AND  ITS  VISCERA 

The  abdominal  cavity  contains  the  digestive  and 
genito-urinary  organs.  It  is  lined  by  a  membrane,  the 
peritoneum,  which  is  a  completely  closed  sac  in  the 
male  and  nearly  closed  in  the  female.  All  the  abdom- 


92  ANATOMY   FOR    NURSES 

inal  viscera  are  in  some  relation  to  the  peritoneum, 
which  forms  a  partial  or  complete  coat  for  them — the 
visceral  peritoneum  to  distinguish  it  from  the  parietal 
which  covers  its  walls.  The  viscera  are  thrust  into  the 
sac  from  behind  and,  as  some  are  pushed  much  fur- 
ther than  others,  there  are  many  cases  in  which  this 
membrane  performs  the  functions  of  binding  the  vis- 
cera to  each  other  or  the  wall  of  the  abdomen  or  sus- 
pending them  from  one  or  the  other. 

The  chief  ligamentous  folds  are,  one  suspending  the 
stomach  from  the  lower  surface  of  the  liver,  the  lesser 
omentum;  a  large  JL old  running  frcm  the  lower  border 
of  the  stomach  nearly  to  the  brim  of  the  pelvis  and 
thence  up  to  the  transverse  colon,  which  it  invests 
and,  indirectly,  suspends  from  the  stomach.  This  is 
called  the  great  omentum,  and  splits  into  the  layers 
of  which  the  upper  follows  the  abdominal  wall  and 
forms  the  posterior  limit  of  the  lesser  cavity  of  the  peri- 
toneum, a  space  behind  the  stomach,  while  the  lower 
runs  down  over  the  small  intestines,  forming  a  liga- 
ment, the  mesentery,  which  binds  them  obliquely  from 
left  to  right  over  the  three  lower  lumbar  vertebrae.  It 
then  runs  over  the  brim  of  the  pelvis,  covers  the  pelvic 
viscera,  forming  the  ligaments  of  the  bladder  and,  in 
the  female,  the  broad  ligament,  a  vertical  fold  which 
cuts  the  pelvis  into  an  anterior  and  posterior  compart- 
ment and  envelopes  the  generative  organs. 

That  part  of  the  alimentary  canal  found  in  the  abdom- 
inal cavity  is  divided  into  the  stomach,  duodenum,  je- 
junum and  ileum  and  the  large  intestine  which  is  sub- 
divided into  cecum,  ascending,  transverse,  and  descending 
colon,  the  sigmoid  flexure  and  the  rectum.  Besides  these 


SPLANCHNOLOGY  93 

hollow  viscera  the  abdomen  contains  the  liver,  spleen, 
pancreas,  kidneys,  and  suprarenal  capsule,  blood  vessels, 
nerves  and  lymphatics. 

The  abdominal  alimentary  canal  is  a  long  hollow  tube, 
expanded  at  various  points,  nearly  thirty  feet  in  length 
and  made  up  of  an  external  peritoneal  or  serous  coat, 
an  internal  mucous  or  digesting  coat,  a  submucous  coat 
of  fibrous  tissue,  circular  and  longitudinal  muscular 
coats.  The  muscular  coats  are  uniformly  distributed 
until  the  large  intestine  is  reached,  when  the  longitu- 
dinal coat  is  gathered  into  bundles  situated  on  the 
front,  back  and  inner  sides.  For  convenience  of  de- 
scription, two  imaginary  lines  may  be  drawn  around 
the  abdomen  cutting  it  into  an  upper,  middle  and  lower 
zone.  One  line  is  drawn  between  the  anterior  superior 
iliac  spines  and  the  other  between  the  ninth  costal  car- 
tilages. Two  other  imaginary  lines  are  now  projected 
upward  from  the  middle  of  Poupart  's  ligament  and  the 
space  is  divided  into  nine  regions.  These  are  named, 
from  above  downward  in  the  middle  line  epigastric,  um- 
bilical and  hypogastric.  Those  on  either  side  are  the 
hypochondriac  right  and  left;  lumbar,  right  and  left; 
and  the  iliac,  right  and  left. 

The  stomach  lies  in  the  left  hypochondriac  (beneath 
the  ribs)  and  the  epigastric.  Its  large  end  is  to  the  left 
and  its  walls  look  forward  and  backward.  It  is  just 
under  the  liver  and  has  the  spleen  close  to  its  left  end, 
which  is  a  little  below  the  heart  from  which  it  is  sepa- 
rated by  the  diaphragm. 

The  duodenum  is  the  part  of  the  small  intestine  suc- 
ceeding the  stomach.  It  first  runs  upward  to  the  under 
surface  of  the  liver,  then  downward,  about  three  inches, 


94  ANATOMY   FOR   NURSES 

and  then  upward  and  to  the  left.  Its  course  is  deter- 
mined by  the  head  of  the  pancreas  around  which  it 
winds.  It  is  nine  inches  long.  The  duct  of  the  pancreas 
and  that  of  the  liver  empty  into  the  descending  part. 

The  jejunum  and  ileum,  about  twenty  feet  long,  are 
the  names  given  to  the  upper  two-fifths  and  the  lower 
three-fifths  of  the  small  intestine.  They  lie  coiled  up 
largely  in  the  umbilical  region,  but  some  of  the  convo- 
lutions fall  into  the  pelvis  and  surrounding  regions. 
The  mucous  coat  of  the  small  intestine  is  thrown  into 
transverse  folds,  valvulce  conniventes,  greatly  increas- 
ing the  absorptive  area  and  retarding  the  floAV  of  semi- 
liquid  food. 

The  small  intestine  empties  into  the  large  in  the  right 
iliac  fossa  two  and  a  half  inches  above  the  commence- 
ment of  the  latter.  The  part  below  the  entrance  is 
called  the  cecum  The  opening  is  the  ileo-cecal  and  just 
below  it  the  vermiform  appendix  opens  into  the  cecum. 
As  this  appendix  has  no  firm  attachment,  except  to  the 
cecum,  its  free  end  may  point  in  any  direction  and  is 
often  attached,  as  the  result  of  adhesions,  to  one  of  the 
pelvic  or  adjacent  abdominal  viscera. 

The  ascending  colon  begins  in  the  right  iliac  region, 
runs  up  through  the  right  lumbar  and  terminates  in  the 
right  hypochondriac,  on  the  under  surface  of  the  liver, 
by  becoming  the  transverse  colon,  which  curves  down- 
ward and  to  the  left  to  just  above  the  umbilicus,  then 
turns  upward  and  to  the  left  to  the  spleen  where  it 
terminates  in  the  descending  colon,  which  runs  from  the 
left  hypochondriac  through  the  left  lumbar  to  terminate 
in  the  left  iliac  in  the  sigmoid  flexure  of  the  colon, 
which  forms  a  loop  whose  position  varies  with  that  of 


Transverse  colon — 1 


Ascending  colon — 1 


Caecum — 
Appen  lix —  | 


SPLANCHNOLOGY 


— Descending  cole 
— Jejunum 


Fig.    11. — Front    view    of    organs.      Semi-diagrammatic. 


96  ANATOMY   FOR   NURSES 

the  body  but  which  runs  over  the  brim  of  the  pelvis  to 
the  middle  of  the  sacrum  when  it  changes  its  name  to 
rectum  which  terminates  at  the  anus.  The  curves  in  the 
large  intestine  made  at  the  liver  and  spleen  are  called 
the  hepatic  and  splenic  flexures.  The  colon  lies  on  the 
right,  above  and  to  the  left  of  the  convolutions  of  the 
small  intestine. 

Food  enters  the  stomach,  where  the  pepsin  and  hy- 
drochloric acid  are  secreted,  begins  to  be  digested  there, 
then  passes  into  the  small  intestine,  where  it  meets  the 
pancreatic  fluid  and  that  of  the  intestine.  Here  diges- 
tion is  continued  and  absorption  goes  on,  decreasing  in 
amount  until  finally,  in  the  lower  part  of  the  large  in- 
testine, there  is  nothing  but  the  waste  matter  left. 

The  liver,  the  largest  glandular  organ  of  the  body, 
weighing  about  four  pounds,  lies  in  the  right  hypo- 
chondriac and  epigastric  regions.  It  is  almost  com- 
pletely covered  by  peritoneum  and  overhangs  the  stom- 
ach, ascending  duodenum,  hepatic  flexure  of  the  colon, 
and  the  right  kidney.  It  has  a  deep  antero-posterior 
fissure  on  its  lower  surface  and,  opposite  this,  a  sus- 
pensory ligament  on  the  upper  surface,  wThich  cut  it 
into  a  large  right  and  small  left  lobe.  Its  convex  upper 
surface  is  in  contact  with  the  diaphragm,  which  sepa- 
rates it  from  the  contents  of  the  thoracic  cavity,  right 
lung  and  heart.  On  its  lower. surface  is  the  gall  blad- 
der, wrhich  holds  its  secretion,  its  ducts  and  the  entrance 
of  the  artery  and  vein  which  are  distributed  to  it. 

The  branches  of  the  portal  vein  and  the  hepatic 
artery  ramify  through  the  liver,  conveying  to  it  a 
large  supply  of  blood,  while  the  branches  of  the  hepatic 


SPLANCHNOLOGY  97 

duct  run  together  to  form  a  single  duct  which  has  a 
communicating  branch,  the  cystic,  by  which  the  bile  is 
conveyed  to  and  from  the  gall  bladder  on  the  under  sur- 
face of  the  liver.  The  union  of  the  cystic  with  the  two 
hepatic  ducts  forms  the  common  bile  duct  which  usually 
unites  with  the  pancreatic  duct  before  emptying  into  the 
lower  part  of  the  perpendicular  duodenum. 

The  Pancreas 

The  pancreas  is  a  compound  racemose  gland,  like  the 
salivary  glands.  It  crosses  the  body  of  the  first  lumbar 
vertebra,  from  which  it  is  separated  by  the  abdominal 
aorta,  inferior  vena  cava  and  the  chief  artery  and  vein 
of  the  intestine,  and  is  covered  only  in  front  by  the  peri- 
toneum. The  large  head  is  embraced  by  the  duodenum 
while  the  tail  is  in  contact  with  the  spleen.  The  upper 
border  is  on  a  level  with  that  of  the  stomach,  and  just 
below  this  border  the  splenic  vein  lies  on  the  back  of  the 
organ.  This  gland  secretes  the  most  important  of  the 
digestive  juices. 

The  Spleen 

The  spleen,  one  of  the  ductless  glands,  lies  in  the 
left  hypochondriac  region,  completely  invested  by  peri- 
toneum which  holds  it  to  the  stomach  and  diaphragm. 
It  corresponds,  by  its  convex  outer  surface,  to  the  ninth, 
tenth,  and  eleventh  ribs.  The  pancreas  is  bound  to  its 
concave  inner  face.  It  receives  one  of  the  largest  of  the 
visceral  branches  of  the  aorta  and  sends  a  vein,  both 
named  splenic,  of  corresponding  size  to  the  portal  cir- 
culation. It  is  invested  by  a  strong  fibrous  capsule  and 
is  subject  to  great  variations  in  size.  Normally  it  is 
about  four  inches  long  by  two  and  a  half  inches  wide. 


98  ANATOMY   FOR   NURSES 

The  Kidneys 

The  kidneys  are  a  pair  of  small  organs,  weighing 
about  a  quarter  of  a  pound,  lying  in  the  lumbar  region 
from  the  eleventh  rib  to  the  iliac  crest  on  the  quadratus 
lumborum  muscle,  whose  outer  borders  extend  a  little 
beyond  the  twelfth  rib.  A  depression  in  the  back  along 
the  outer  edge  of  the  erector  spinas  muscle,  indicates 
their  position.  The  right  kidney  is  a  little  lower  than 
the  left.  The  kidneys  lie  behind  the  peritoneum,  which 
is  usually  separated  from  them  by  some  fat.  The  right 
has  the  ascending  colon  and  descending  duodenum  in 
front  of  it.  The  left  has  the  descending  colon.  Each 
kidney  has  a  deep  notch  the  hilum  on  its  inner  border 
leading  into  a  cavity,  which  lodges  the  duct  and  ves- 
sels of  the  organ.  These  are  arranged  with  the  vein  in 
front,  duct,  or  ureter,  behind  and  artery  between. 

The  Urinary  Bladder 

The  bladder  occupies  the  anterior  part  of  the  pelvic 
cavity,  is  a  hollow  sac  made  up  of  an  internal  mucous, 
two  muscular,  and  a  partial  serous  coat,  having  the  ure- 
ters conveying  the  excretion  of  the  kidneys  into  it  and 
the  urethra  conveying  it  away.  The  bladder  and  its  ap- 
pendages rest  on  the  front  of  the  rectum.  In  the  female 
the  internal  generative  organs  lie  between  bladder  and 
rectum.  In  both  male  and  female,  convolutions  of  the 
small  intestines  fall  into  the  pelvic  cavity  and  come  in 
contact  with  the  bladder  and  in  both  the  peritoneum  cov- 
ers the  posterior  half  of  the  organ.  The  urethra  in  the 
female  is  very  short,  about  two  inches,  and  terminates  at 
the  upper  part  of  the  vaginal  cleft.  In  the  male  this 
tube  runs  the  length  of  the  penis.  In  the  male  the  pros- 


SPLANCHNOLOGY  99 

tate  gland  surrounds  the  neck  of  the  bladder  and  the 
seminal  vesicles  with  the  vasa  deferentia  internal  to 
them,  form  a  triangle  between  bladder  and  rectum.  In 
the  female  these  structures  are  wanting  and  their  place 
is  taken  by  the  upper  part  of  the  vagina,  the  uterus, 
and  its  appendages. 

The  Generative  Organs  in  the  Female 

These  are  the  uterus,  ovaries.  Fallopian  tubes  and  the 
vagina. 

The  uterus  is  shaped  like  a  flattened  pear  with  its 
large  end  upward  in  the  pelvic  cavity  and  its  small  end 
surrounded  by  the  vagina.  It  is  covered  by  peritoneum, 
except  where  the  vagina  grasps  it,  and  leans  forward 
and  upward.  Its  cavity  communicates  by  a  large  open- 
ing, the  os,  through  a  constricted  neck,  with  the  vagina, 
and  at  each  upper  angle,  through  a  Fallopian  tube, 
Avith  the  peritoneal  cavity.  There  is,  therefore,  a  hole 
in  the  female  peritoneum  which  does  not  exist  in  the 
male  and  a  consequent  danger  of  peritonitis.  The 
uterus  is  held  in  position  by  folds  of  peritoneum  be- 
hind, in  front,  and  on  each  side,  and  by  a  round  liga- 
ment which  extends,  from  just  below  the  Fallopian 
tube  through  the  inguinal  canal  to  the  labium  majus. 
The  lateral  ligament  (broad  ligament)  is  a  vertical 
band  which  encloses  the  tubes,  ovaries  and  round  liga- 
ment and  stretches  to  the  lateral  wall  of  the  pelvis.  It 
shuts  off  a  cavity  behind,  which  lies  between  the  rectum 
and  uterus,  is  known  as  the  pouch  of  Douglas,  and  can 
hold  a  large  amount  of  fluid. 

The  ovaries  lie  one  on  each  side  of  the  uterus  and  are 
held  to  it  by  a  round  ligament  developed  in,  the  broad 


100  ANATOMY   FOR   NURSES 

ligament.  Its  outer  end  is  nearly  in  contact  with,  the 
iliac  vein  and,  on  the  right  side,  it  often  touches  the 
appendix.  To  its  outer  end,  which  is  the  higher,  the 
fimbriated  extremity  of  the  Fallopian  tube  is  attached. 
The  function  of  the  ovary  is  to  produce  eggs,  that  of 
the  tube  to  convey  the  eggs  to  the  uterus,  and  of  the 
latter  to  hatch  them.  The  hatching  is  called  gestation 
and  the  act  of  birth  parturition,  which  takes  place 
through  the  vagina. 

The  vagina  is  a  tube  with  anterior  and  posterior 
walls  the  upper  inch  of  which  is  in  the  pelvic  cavity, 
covered  on  its  posterior  wall  by  peritoneum.  Its  an- 
terior wall  is  in  contact  with  the  bladder.  Below  it 
terminates  in  a  slit-like  aperture,  cut  vertically,  which 
is  surrounded  by  two  thin  folds,  nymphae  or  labia 
minora,  which  are  overlapped  and  hidden  by  larger 
folds,  labia  majora,  which  unite  over  the  pelvic  symphysis 
in  the  mons  veneris.  If  the  labia  are  separated  a  trian- 
gular space  will  be  seen  between  the  nymphae  in  front 
called  the  vestibule.  At  the  back  of  the  vestibule  is  the 
opening  of  the  urethra  and  just  in  front  of  it  the  clitoris. 
These  appearances  are  collectively  called  the  vulva. 

The  Generative  Organs  in  the  Male 

The  chief  male  generative  organs  lie  outside  the  pel- 
vic cavity  and  consist  of  penis  and  testicles. 

The  penis  consists  of  two  parallel  bodies,  the  corpora 
cavernosa,  bound  together  by  fibrous  tissue,  and  a  longer 
body  opposite  the  interval  between  the  cavernosa  below 
called  corpus  spongiosum,  which  carries  the  urethra  and 
turns  up  in  front  over  the  end  of  the  cavernosa  to  form 


SPLANCHNOLOGY  101 

— — ^ 

the  glans  penis  which  is  pierced  by  the  opening  of  the 
urethra,  the  meatus  urinarius.  Posteriorly  the  three 
bodies  separate  to  form  the  root  of  the  penis ;  the  lateral 
roots,  the  origin  of  the  cavernosa,  being  attached  to  the 
rami ;  and  the  central  body,  or  bulb,  being  attached  to 
the  triangular  ligament. 

The  testicle,  originally  an  abdominal  organ  which 
descends  through  the  inguinal  canal  to  the  scrotum,  is 
the  secreting  organ  in  the  male  analagous  to  the  ovary 
in  the  female.  The  two  testicles  lie  in  a  pouch  of  skin 
and  unstriped  muscular  fibers,  lined  by  a  serous  mem- 
brane, called  the  scrotum.  The  serous  membrane  covers 
the  testicle  and  lines  the  scrotal  sac.  It  is  called  tunica 
vaginalis.  The  testicle  is  suspended  by  a  rounded  cord 
made  up  of  the  cremaster  muscle,  blood  vessels,  nerves 
and  lymphatic  and  the  duct  of  the  testicle,  the  vas 
deferens.  The  vas  enters  at  the  hole  in  the  external 
oblique,  passes  along  the  inguinal  canal,  crosses  the 
external  iliac  artery  and  vein  to  the  base  of  the  bladder 
where  it  joins  a  coiled  tube,  the  seminal  vesicle,  a  small 
reservoir  for  the  seminal  fluid,  forming  the  ejaculatory 
duct  which  passes  the  seminal  fluid  into  the  prostatic 
portion  of  the  urethra. 

The  passage  of  the  testicle  and  the  presence  of  the 
spermatic  cord  leave  a  potential  canal  in  the  lower 
abdominal  wall  along  which  a  portion  of  the  intestine 
may  run  in  forming  an  inguinal  hernia.  As  the  round 
ligament  is  the  only  structure  in  the  female  which  oc- 
cupies this  canal,  the  chance  of  this  form  of  hernia  is 
much  lessened  in  women. 


102  ANATOMY   FOR   NURSES  f\    V( 

9 

THE  THORACIC  VISCERA 

The  thorax  is  divided  into  two  pleural  and  a  cardiac 
space,  each  lined  by  serous  membrane,  and  a  space  be- 
tween, the  mediastinum,  which  transmits  many  impor- 
tant structuresT" 

The  cardiac  space  is  surrounded  by  a  membrane,  the 
fibrous  pericardium,  cone-shaped  with  its  large  end  below, 
corresponding  to  the  upper  face  of  the  central  and  left 
leaflets  of  the  trefoil  tendon  of  the  diaphragm.  Above 
the  cone  contracts  to  .blend  with  the  fibrous  coat  of  the 
great  blood  vessels  attached  to  the  heart.  The  pericar- 
dium lies  between  the  lungs  on  either  side,  the  sternum 
and  left  costal  cartilage  from  the  third  to  the  seventh  in 
front,  and  the  vertebral  column  behind,  from  which  it 
is  separated  by  the  root  of  the  lungs,  esophagus,  and 
thoracic  aorta.  It  is  lined  by  a  serous  pericardium 
which  covers  its  walls  and  the  exterior  of  the  heart 
and  its  vessels. 

The  heart  has  its  small  end,  or  apex,  directed  down- 
ward and  to  the  left,  corresponding  to  the  space  be- 
tween the  fifth  and  sixth  ribs  about  three  inches  to  the 
left  of  the  midline.  The  base,  directed  backward,  up- 
ward, and  to  the  right,  corresponds  to  the  thoracic 
vertebrae  from  the  fifth  to  the  eighth  inclusive.  The 
exterior  of  the  heart  is  marked  by  two  furrows  at 
right  angles  to  each  other.  The  upper  furrow  passes 
transversely  around  the  organ,  lodges  a  large  venous 
and  arterial  channel  and  indicates  the  position  of  the 
septum  between  auricles  and  ventricles.  The  vertical 
groove  passes  to  the  right  of  the  apex,  lodges  vessels 
and  indicates  the  position  of  the  interventricular  septum. 


SPLANCHNOLOGY  103 

The  interior  of  the  heart  is  divided  into  two  upper 
cavities,  the  right  and  left  auricles,  and  two  lower,  the 
right  and  left  ventricles.  The  right  side  of  the  heart  is 
the  venous  and  the  left  the  arterial. 

The  right  auricle  receives  the  inferior  vena  cava  at 
its  lower  and  the  superior  vena  cava  at  its  upper  part. 
These  pour  in  the  blood  from  all  parts  of  the  body  ex- 
cept the  heart,  whose  return  circulation  goes  into  the 
same  cavity  through  the  coronary  sinus.  The  upper 
front  portion  is  prolonged  into  a  projection  like  a  dog's 
ear,  called  the  auricular  appendix,  which  overlaps  the 
aorta. 

The  left  auricle,  situated  behind  and  to  the  left  of  the 
right,  also  has  an  auricle  which  overlaps  the  pulmonary 
artery.  The  cavity  receives  the  pulmonary  veins,  four 
in  number.  The  two  left  often  unite  so  as  to  leave  but 
three  openings  for  their  entrance.  Each  auricle  has  a 
large  opening  through  the  auriculo-ventricular  septum, 
by  which  blood  is  poured  into  the  corresponding  ven- 
tricle. 

The  right  ventricle  occupies  nearly  the  whole  of  the 
front  of  the  heart.  It  terminates  above  in  a  cone  which 
gives  rise  to  the  pulmonary  artery,  and  receives,  behind 
that  point,  the  venous  blood  through  the  right  auriculo- 
ventricular  opening.  The  latter  is  guarded  by  a  valve 
made  up  of  three  flaps,  the  tricuspid,  to  which  are  at- 
tached small  tendons,  chordae  tendineae,  the  termination 
of  little  muscles,  the  papillary,  which  are  attached  to 
the  walls  of  the  ventricle  and  keep  the  valves  from 
being  forced  into  the  auricle  when  the  ventricle  con- 
tracts. The  opening  of  the  pulmonary  artery  is  guarded 
by  three  valves,  shaped  like  half  cups,  called  semilunar. 


104  ANATOMY    FOR    NURSES 

The  left  ventricle  makes  up  most  of  the  back  of  the 
heart,  though  it  forms  the  front  of  the  apex.  It  has  a 
left  auriculo-ventricular  opening  guarded  by  a  two 
napped  valve,  the  bicuspid  or  mitral,  which  has  chordae 
tendineae  and  columnae  carneaa  (papillary)  just  as  on  the 
right  side.  Behind  and  to  the  right  of  the  pulmonary 
opening  of  the  right,  this  ventricle  gives  origin  to  the 
aorta,  which  is  guarded  by  three  sernilunar  valves  like 
those  in  the  pulmonary.  The  left  ventricle  has  walls 
about  twice  as  thick  as  those  of  the  right.  The  right 
pumps  blood  into  the  lungs  only;  the  left,  throughout 
the  body.  The  left  auricle  is  also  thicker  than  the 
right,  but  the  difference  is  not  so  great. 

The  two  auricles  contract  to  fill  the  ventricles.  Then 
the  bicuspid  and  tricuspid  valves  close  to  prevent  flow- 
ing back  (regurgitation)  of  blood  into  the  auricles. 
The  contraction  of  the  ventricles  drives  the  blood  into 
the  pulmonary  artery  and  the  aorta.  Then  the  semi- 
lunar  valves  close  to  prevent  regurgitation  into  the  ven- 
tricles. Injury  or  disease  of  the  valves  will  cause  a 
leak  and  the  heart  has  to  grow  in  size  and  power  to 
compensate  the  leakage. 

The  Pleural  Cavities  and  Lungs 

Each  pleural  cavity  is  the  space  between  the  ribs  on 
the  sides  and  behind  and  the  pericardium  internally. 
Each  is  a  closed  sac  lined  by  the  parietal  pleura.  The 
two  sacs  do  not  touch,  though  they  are  very  close  to- 
gether at  the  level  of  the  second  rib.  Within  these  sacs 
the  lungs  move  freely,  covered  by  the  visceral  or  pul- 
monary pleura,  a  reflection  of  the  parietal.  The  cavities 
are  cone-shaped,  with  the  apices  upward  and  extending 


SPLANCHNOLOGY  105 

above  the  clavicle  into  the  root  of  the  neck.  The  left 
extends  lower  down  than  the  right,  because  the  liver 
pushes  the  diaphragm  up  on  the  right. 

The  lungs  correspond  in  shape  to  the  pleural  cavities. 
The  left  is  slightly  larger  than  the  right,  but  is  hollowed 
out  on  its  inner  side  by  the  projection  of  the  heart. 

The  bronchi,  two  cartilaginous  tubes  formed  by  the 
bifurcation  of  the  trachea,  with  the  pulmonary  arteries 
and  veins,  form  the  chief  elements  of  the  root  of  the 
lungs,  which  enters  at  a  depression  above  the  middle 
of  the  inner  surface.  These  divide  and  subdivide  un- 
til small  air  cells  are  formed  around  which  the  minute 
vessels  are  so  arranged  that  the  inspired  air  can  ex- 
change its  oxygen  for  the  gases  contained  in  the  venous 
blood.  The  presence  of  this  air  causes  the  lungs  to 
float  in  water. 

The  apex  of  the  lung  projects  into  the  neck  two  and  a 
half  inches  above  the  first  rib  and  is  a  blunt  point. 
The  base  is  deeply  hollowed  out  by  the  dome-shaped  dia- 
phragm. The  outer  surface  is  broad  and  convex,  to 
conform  to  the  inner  face  of  the  ribs.  The  anterior 
border  is  thin  and  sharp,  to  fit  into  the  interval  between 
the  front  of  the  pericardium  and  the  back  of  the  ster- 
num and  ribs.  The  posterior  border  is  round  and  thick 
to  fill  in  the  deep  groove  beside  the  vertebral  column 
and  on  the  front  of  the  ribs  behind  the  angle.  The  in- 
ner surface  is  concave  to  fit  the  pericardium. 

The  Mediastinum 

The  mediastinum  is  the  irregular  space  between  the 
pleurae.  Draw  a  line  from  the  junction  of  the  first  and 
second  pieces  of  the  sternum  upward  and  backward  to 


106  ANATOMY   FOR   NURSES 

the  lower  border  of  the  fourth  thoracic  vertebras.  All 
the  space  above  this  line  is  the  superior  mediastinum.  It 
contains  the  innominate  artery,  and  its  vein,  thoracic 
part  of  the  left  corotid  and  subclavian  arteries,  parts  of 
the  trachea,  esophagus,  pneumo gastric  and  phrenic 
nerves  and  many  other  structures. 

The  remainder  of  the  interpleural  space  is  subdivided 
into  anterior,  middle,  and  posterior  mediastinal  cavities. 

The  anterior  mediastinum  is  the  space  in  front  of  the 
pericardium. 

The  middle  mediastinum  is  the  pericardium  and  its 
contents. 

The  posterior  mediastinum  is  the  space  between  the 
back  of  the  pericardium  and  the  front  of  the  thoracic 
vertebras  below  the  fourth.  It  contains  the  esophagus, 
descending  aorta,  thoracic  duct,  part  of  the  pneumogas- 
tric  nerves,  azygos  veins,  etc. 


CHAPTER  VI 
ARTERIES  AND  VEINS 

The  circulation  of  the  blood  starts  at  the  heart  which 
is  a  four  chambered  pump,  having  two  right  and  two 
left  chambers.  The  right  side  is  for  venous  blood  and  the 
left  for  arterial.  Starting  from  the  left  lower  chamber  the 
great  aorta  curves  upward  about  two  inches,  bends 
abruptly  to  the  left  for  nearly  three  inches  and  then 
turns  sharply  downward  to  finally  divides  into  tAvo 
branches  near  the  fourth  lumbar  vertebra,  its  two 
branches  going  to  the  lower  extremities  and  the  pel- 
vis. As  it  starts  it  gives  two  branches  to  the  heart  and 
then,  in  its  transverse  part,  a  large  branch  which  splits 
into  two  to  supply  the  right  half  of  the  head  and  neck 
and  the  right  upper  extremity.  A  second  branch  of 
smaller  size  does  the  same  work  for  the  left  side  of  the 
head  and  neck,  while  a  third  is  for  the  left  upper  ex- 
tremity. The  main  aorta,  between  these  branches  and 
its  bifurcation,  (splitting  in  two)  gives  off  the  branches 
to  the  remainder  of  the  body. 

The  venous  blood  is  poured  into  the  upper  right 
chamber  of  the  heart  by  two  vessels  called  cavae,  supe- 
rior and  inferior.  The  superior  collects  blood  from  the 
head,  neck  and  both  upper  extremities;  the  inferior 
from  the  lower  extremities,  pelvis,  and  greater  part  of 
the  abdominal  contents  and  walls.  Between  these  two  a 

107 


108  ANATOMY    FOR    NURSES 

set  of  veins  called  azygos  take  same  blood  from  the 
abdomen  and  more  from  the  thorax.  Veins  are  divided 
into  two  sets,  superficial,  such  as  are  seen  on  the  back 
of  the  hand,  and  deep  which  accompany  the  arteries  of 
the  same  name.  The  course  of  the  circulation  is  to 
pass  away  from  the  heart  through  the  arteries  and  to 
return  to  the  heart  through  the  veins.  There  is  no 
direct  communication  between  an  artery  and  a  vein; 
but  as  the  arteries  get  smaller,  their  coats  get  thinner 
until  they  terminate  in  very  small  thin  vessels  called 
capillaries  through  whose  wall  the  gases  in  the  blood 
can  be  given  off  to  the  tissue  and  the  gases  in  the  tissue 
can  be  taken  up  by  the  blood  forming  an  exchange  of 
gases  just  the  reverse  of  that  in  the  lungs.  Roughly  the 
lungs,  removing  injurious  gases,  take  out  C02  from  the 
blood  and  replace  it  with  0 ;  while  the  tissues  take  out 
0  and  give  up  C02.  Gradually  the  capillaries  get 
thicker  walls  and  unite  with  each  other  to  form  vein- 
lets,  which  again  unite  to  form  small  veins,  which  again 
unite  and  so  the  process  is  repeated  until  only  two 
veins  remain — superior  and  inferior  venae  cavas.  The 
arteries,  therefore,  constantly  grow  smaller  by  dividing 
or  giving  off  branches;  and  the  veins  grow  larger  as 
they  approach  the  heart,  by  the  union  of  two  or  more 
small  veins  and  the  reception  of  tributaries;  that  is  the 
veins  are  like  tracing  a  river  from  sources  to  mouth 
and  the  arteries  like  tracing  the  same  from  mouth  to 
various  sources.  At  two  points,  lungs  and  liver,  there 
is  a  special  arrangement  of  blood  vessels  so  important 
as  to  require  special  study.  Only  that  in  the  lungs  will 
be  now  mentioned. 


ARTERIES    AND   VEINS  109 

PULMONARY  CIRCULATION 

All  the  blood  in  the  body,  at  one  time  or  another, 
is  poured  through  the  upper  right  chamber  of  the 
heart  (the  right  or  venous  auricle),  and  descends  from 
that  into  the  chamber  below — right  or  venous  ventricle. 
From  this  it  is  driven,  by  contraction  of  the  ventricle 
through  the  pulmonary  artery,  which  splits  into  right 
and  left  pulmonary  arteries,  into  the  lungs,  when  these 
arteries  divide  and  subdivide  as  in  other  parts  of  the 
body,  until  their  capillaries  finally  are  placed  in  such 
relation  to  the  air  cells  of  the  lungs  that  the  exchange 
of  gases  alluded  to  above  can  take  place.  All  the  blood 
in  the  body  thus  passes  through  the  lungs  where  it  is 
oxygenated,  but  does  not  nourish  the  lungs,  which 
must  have  blood  like  any  other  tissue,  and  get  it  from 
a  set  of  bronchial  branches  coming  from  the  aorta. 
This  aerated  blood  is  now  returned  to  the  heart  through 
a  set  of  veins  called  pulmonary  which  enter  the  upper 
left  chamber  or  auricle  of  the  heart,  called  the  arterial 
auricle.  The  pulmonary  circulation  is  thus  a  sort  of 
loop  or  side  track  in  the  general  circulation  and  pre- 
sents the  anomaly  of  an  artery  carrying  venous  and  a 
set  of  veins  carrying  arterial  blood.  From  the  left  auri- 
cle the  blood  is  poured  into  the  left  or  arterial  ven- 
tricle and  thence  is  pumped  through  the  aorta  and  its 
branches  to  the  remotest  parts  of  the  body,  whence  it 
is  returned  through  capillaries,  veinlets  and  veins  to 
the  heart  to  start  over  the  same  process  again.  As, 
therefore,  the  arteries  form  a  continuous  set  of  tubes 
leading  away  from  the  heart,  and  the  veins  a  continuous 
set  leading  back,  it  is  obvious  that  if  one  wants  to  trace 


110  ANATOMY  FOR   NURSES 

a  substance  in  its  course  from  or  to  a  given  part  of  the 
body,  it  is  only  necessary  to  know  what  vessels  supply 
that  part.  If  one  could  place  a  tag  on  a  certain  blood 
corpuscle  and  route  it  for  the  big  toe,  its  course  would 
be  as  definite  as  if  it  had  a  railroad  track  to  guide  it, 
and  like  that  would  be  capable  of  interruption  or  mis- 
carriage at  various  branch  lines.  It  would  leave  the 
heart  at  the  aortic  opening,  pass  through  the  various 
parts  of  the  aorta  to  its  bifurcation  where  it  would 
enter  a  primitive  iliac  artery  and  proceed  through  an 
external  iliac,  femoral  and  popliteal  to  the  bifurcation 
of  the  latter,  thence  through  the  anterior  tibial  and 
dorsalis  pedis  to  the  great  toe.  Now  it  would  have 
the  choice  of  two  routes  for  its  return.  If  it  went 
by  the  deep  vein,  it  would  start  by  a  satellite 
accompanying  the  dorsal  artery  of  the  foot,  through  an 
anterior  tibial,  popliteal,  femoral,  external  and  common 
iliac  into  the  inferior  vena  cava  and  thence  into  the 
venous  auricle,  venous  ventricle,  pulmonary  artery, 
right  or  left  lung  as  the  case  might  be,  back  to  the  arte- 
rial auricle  through  a  pulmonary  vein,  thence  to  the 
arterial  ventricle  and  be  ready  at  the  mouth  of  the 
aorta  to  start  on  the  same  journey  or  be  routed  to  the 
little  finger,  the  eye,  ear,  brain  or  any  other  part  of  the 
anatomy.  Its  second  route  from  the  big  toe  would  be 
to  choose  a  veinlet  of  a  long  vein  called  internal  saph- 
enous,  which  would  conduct  it  along  the  inner  side  of  the 
foot,  ankle,  leg  and  thigh  until  it  pierced  the  fascia 
lata  just  below  Poupart's  ligament  to  empty  into  the 
femoral  vein,  after  which  its  course  would  be  the  same 
as  that  just  traced.  It  is,  therefore,  plain  that  the  study 
of  the  arteries  and  veins  is,  in  no  inconsiderable  meas- 


systemc 

Fig.   12. — Diagram  of  entire  circulation. 


ARTERIES   AND   VEINS  111 

ure,  merely  a  learning  of  names  and  not  of  facts;  and 
that  a  knowledge  of  the  parts  formed  by  the  skeleton 
will,  in  the  main,  furnish  the  student  with  the  names. 
The  two  coronary  arteries,  for  the  supply  of  the  heart 
itself,  would  spring  just  after  the  origin  of  the  aorta; 
then  would  come  the  innominate  which  quickly  subdi- 
vides into  the  right  common  carotid,  going  upward, 
and  the  right  subclavian  going  outward.  The  left  sub- 
clavian  has  a  separate  origin  (the  third)  from  the  trans- 
verse aorta,  and  has  a  thoracic  portion  similar  to  the 
innominate.  Getting  to  the  middle  of  the  clavicle,  each 
subclavian  becomes  the  counterpart  of  the  other  and 
the  right  only  will  be  traced.  From  the  inner  end  of 
the  collar  bone  to  its  outer  third  the  artery  and  vein 
are  called  subclavian;  from  there  to  the  surgical  neck 
of  the  humerus,  axillary ;  from  there  to  the  bend  of  the 
elbow  the  artery  is  the  brachial,  but  there  are  two 
brachial  veins,  one  on  each  side.  At  the  bend  of  the 
elbow,  in  other  words  as  soon  as  there  are  two  bones,  the 
artery  bifurcates  and  the  two  are  known  as  radial  or 
ulnar  according  as  they  are  found  on  the  inner  or  outer 
bone.  They  continue  under  these  names  into  the  hand 
Avhere  they  communicate,  and  each  has  two  veins. 

From  the  bifurcation  of  the  aorta  the  names  are  to 
the  brim  of  the  pelvis  common  or  primitive  iliac  which 
divides  into  an  internal  iliac  for  the  pelvis  and  an  ex- 
ternal for  the  lower  extremity,  which  changes  its  name 
at  Poupart's  ligament  to  become  femoral  and  that  be- 
comes popliteal  at  the  lower  third  of  the  femur  and 
divides  into  anterior  and  posterior  tibial  just  below  the 
knee  joint.  These  pass  down  on  'the  front  and  back  of 
the  leg  respectively,  and  are  distributed  to  structures 


112  ANATOMY   FOR   NURSES 

as  they  descend,  the  anterior  becoming  the  artery  of  the 
back  of  the  foot  (dorsalis  pedis),  while  the  posterior 
divides  into  internal  and  external  plantar  arteries  for  the 
sole. 

The  right  and  left  carotid  arteries,  above  the  clavicle, 
pass  np  to  the  thyroid  cartilage  and  divide  into  the 
internal  and  external  carotids,  the  internal  to  enter  the 
skull  through  an  opening  in  the  temporal  bone  and  sup- 
ply the  interior  of  the  skull  and  its  contents ;  while  the 
external,  dividing  into  temporal  and  deep  facial,  or  inter- 
nal maxillary,  supplies  the  interior  of  the  skull  and 
face. 

THE  AORTA 

The  aorta  extends  from  the  base  of  the  heart  to  the 
lower  border  of  the  fourth  lumbar  vertebra  and  is  di- 
vided into  ascending,  transverse  and  descending,  the  lat- 
ter having  a  thoracic  and  an  abdominal  portion. 

The  Ascending  Aorta 

The  ascending  aorta,  about  two  inches  long,  lies  a 
quarter  of  an  inch  behind  the  sternum,  in  the  pericar- 
dium, overlapped  by  the  right  auricular  appendix  and 
having  the  pulmonary  artery  first  in  front  and  then  to 
its  left.  It  terminates  by  becoming  the  transverse  aor- 
ta at  the  upper  border  of  the  second  right  costal  car- 
tilage, where  the  aortic  valves  may  be  heard,  where  the 
pericardium  blends  with  the  outer  coat  of  the  vessel. 

It  gives  off  the  two  coronary  arteries,  right  or  an- 
terior and  left  or  posterior.  They  descend  in  the  cor- 
responding interventricular  grooves  and  anastomose 
at  the  apex  of  the  heart,  after  giving  off  lateral 


ARTERIES   AND   VEINS  113 

branches  at  the  auriculo-ventricular  grooves  which  em- 
brace the  heart  transversely  and  inosculate  with  each 
other. 

The  Transverse  Aorta 

The  transverse  aorta,  starting  at  the  upper  second 
right  cartilage,  passes  backward,  downward,  and  to  the 
left  to  the  lower  border  of  the  fourth  dJifel  vertebra 
where  it  becomes  the  descending  aorta.  It  lies  in  the 
superior  mediastinum  about  an  inch  below  the  sternal 
notch  and  is  overlapped  greatly  by  the  left  pleura  and 
lung.  Across  its  upper  front  runs  the  left  innominate 
vein,  the  left  tenth  and  phrenic  nerves,  wrhile  behind 
it  is  in  close  contact  with  the  trachea,  esophagus,  tho- 
racic duct  and  left  recurrent  laryngeal  nerve.  The  bi- 
furcation of  the  pulmonary  artery  is  below  it. 

It  gives  off,  from  its  upper  side,  from  right  to  left  the 
arteria  innominata,  left  common  carotid,  and  left  sul)- 
clavian. 

The  Thoracic  Aorta 

The  thoracic  aorta  begins  at  the  lower  border  of  the 
fourth  and  terminates  on  the  body  of  the  twelfth  dorsal 
vertebra  by  becoming  the  abdominal  aorta. 

It  lies  in  the  posterior  mediastinum  at  first  on  the  left 
side  and  then  011  the  front  of  the  vertebrae,  inclining 
forward  and  to  the  right.  The  esophagus,  bearing  the 
two  tenth  (pneumogastric)  nerves,  crosses  it  obliquely 
in  front,  as  does  the  root  of  the  left  lung.  The  vena 
azygos  major  and  thoracic  duct  are  to  its  inner  side. 
It  is  nearly  covered  by  the  left  pleura  and  lung.  In 
front,  below  the  fifth  vertebra,  lies  the  pericardium  and 
heart. 


114  ANATOMY   FOR    NURSES 

Branches. — These  are  bronchial,  intercostal,  pericardiac,  eso- 
plwgcal  and  mediastmal.  The  last  three  are  small  twigs  given 
the  structures  whose  names  they  bear. 

The  bronchial  arteries  pass  outward  in  the  root  of  the  lungs  and 
supply  the  substance  of  those  organs. 

The  intercostal  arteries  are  ten  pairs  'which  run  in  the  inter- 
costal spaces,  except  the  upper,  to  supply  the  ribs  and  structures 
adjacent  to  them,  and  to  anastomose  with  branches  of  the  internal 
mammary  in  front. 

* 

The  Abdominal  Aorta 

The  abdominal  aorta  begins  on  the  body  of  the 
twelfth  thoracic  vertebra  and  terminates,  greatly  di- 
minished, on  the  body  of  the  fourth  lumbar  by  dividing 
into  right  and  left  common  iliacs. 

This  artery  passes  through  the  aortic  opening  be- 
hind the  diaphragm,  rests  on  the  bodies  of  the  vertebras 
and  lies  behind  the  peritoneum  and  many  of  the  abdom- 
inal viscera.  It  has  the  stomach  in  front,  but  dis- 
tant, the  pancreas  and  transverse  duodenum  in  imme- 
diate contact,  and  the  transverse  colon  in  front  and  dis- 
tant. On  its  right  side,  throughout,  is  the  inferior  vena 
cava  while  the  mesentery  of  the  small  intestine  is  at- 
tached obliquely  across  it.  The  left  lumbar  veins  run 
behind  and  the'  left  renal  in  front. 

Branches. — The  branches,  numerous  and  important,  are  divided 
into  parietal  and  visceral. 

The  parietal  branches  are  phrenio,  lumbar,  and  sacra  media. 

The  phrenic  are  just  muscular  branches,  for  the  diaphragm. 
They  sometimes  come  from  one  of  the  branches  of  the  aorta,  ram- 
ify over  the  diaphragm  and  inosculate  with  each  other  and  with 
the  mUjSCulo-phrenic  of  the  internal  mammary. 

The  lumbar  are  four  pairs  which  correspond  to  the  intercostals. 
They  have  no  intercostal  spaces  in  which  to  run,  but  spread  out  in 
the  broad  muscles  of  the  abdomen,  supplying  them  and  inosculat- 


Fig.    13. — The   aorta    and    its   branches. 


tfl 


ARTERIES   AND   VEINS  115 

ing  with  a  branch  of  the  external  iliac  which  corresponds  to,  and 
anastomoses  with,  the  internal  mammary. 

The  sacra  media  is  a  small  vessel  running  down  the  sacrum. 

The  remaining  branches  are  divided  into  digestion  and  genito- 
urinary. !  [j 

In  the  first  set  are  the  oelmc  axis,  superior  and  inferior  mes- 
enteric,  while  the  second  comprises  the  renal  and  suprarenal,  the 
spermatic  in  the  male,  and  ovarian  in  the  female. 

The  Celiac  Axis 

The  celiac  axis  is  a  short  trunk  springing  from  the 
aorta  immediately  after  it  pierces  the  diaphragm  juts 
forward  and  breaks  up  into  three  branches,  gastric,  he- 
patic, and  splenic. 

The  gastric  reaches  the  lesser  curvature  of  the  stom- 
ach by  passing  up  behind  that  organ  and  then  runs  to 
the  right  to  meet  the  pyloric  from  the  hepatic  and  form 
a  loop  along  the  upper  part  of  the  stomach  from  which 
small  branches  run  down  both  its  faces. 

The  hepatic  runs  first  to  the  right  and  then  upward 
in  the  lesser  omentum  to  the  under  surface  of  the  liver 
where  it  divides  into  right  and  left  hepatic  arteries  for 
the  two  lobes  of  the  liver  to  which  it  supplies  arterial 
blood.  It  has  the  bile  duct  on  its  right  and  the  portal 
vein  between  and  behind  duct  and  artery. 

It  gives  off  a  branch  to  the  gall  bladder  and  a  large 
branch  which,  after  aiding  in  the  supply  of  duodenum 
and  pancreas,  runs  to  the  left  in  the  great  omentum 
along  the  great  curvature  of  the  stomach  to  meet  a  sim- 
ilar branch  of  the  splenic  and  form  a  loop  which  gives 
ascending  branches  to  both  faces  of  the  stomach  and 
descending  branches  to  the  omentum.  These  arteries 
are  called  gastro-epiploica  dextra  and  sinistra  (arteries 
of  the  stomach  and  omentum,  right  and  left). 


116  ANATOMY   FOR   NURSES 

The  splenic  is  the  largest  branch  of  this  axis.  It  runs 
along  the  upper  border  of  the  pancreas  behind  the  stom- 
ach, to  the  spleen  with  the  splenic  vein  below  it  and  be- 
hind the  pancreas.  Most  of  its  blood  is  poured  into  the 
spleen  (a  blood  elaborating  gland),  but  it  gives  large 
branches  to  the  pancreas  and  great  end  of  the  stomach 
(vasa  brevia)  in  addition  to  the  gastro-epiploica  sin- 
istra. 

The  Superior  Mesenteric 

The  superior  mesenteric  is  a  very  large  vessel  which 
supplies  the  intestinal  canal  from  the  duodenum  to  the 
middle  of  the  transverse  colon.  It  arises  just  below  the 
celiac  axis,  behind  the  pancreas,  runs  between  that 
gland  and  the  transverse  duodenum  into  the  mesentery 
and  thence,  with  a  decided  curve,  convex  to  the  left, 
passes  to  the  right  iliac  fossa.  It  is  accompanied  by  a 
vein  lying  to  its  right  and,  as  the  mesentery 
moves  freely,  is  the  most  movable  artery  in  the  abdo- 
men. 

Branches. — This  artery  is  distributed  by  a  number  (eight  to 
eighteen)  of  branches  from  its  convex  left  side  called  vasa  intestini 
tennis,  and  by  three  branches  on  the  right  named,  from  below  up, 
ileo-colic,  colica  dextra  and  calica  media,  besides  a  small  branch  to 
the  pancreas  and  duodenum  which  inosculates  with  a  similar  branch 
derived  from  the  hepatic. 

The  vasa  intestini  tenuis  are  all  distributed  in  the  same  way. 
Each  divides,  after  a  short  course,  into  an  upper  and  a  lower 
branch.  The  upper  of  one  and  the  lower  of  the  other  run  to- 
gether and  form  a  loop.  From  these  loops  branches  spring  which 
divide  and  unite  to  form  a  second  loop,  and  from  this  another  loop 
may  be  formed.  There  are  usually  three  series  of  loops,  each 
smaller  than  its  predecessor,  though  sometimes  more.  From  the 
last  loop  spring  branches  (vasa  recta)  which  do  not  divide  but 
run,  one  in  front  and  the  other  behind,  around  the  intestine  and 
anastomose  with  each  other  in  its  wralls. 


Fig.   14. — Superior  mesenteric  artery. 


ARTERIES    AND    VEINS  117 

On  the  concave  side  the  distribution  is  similar  but  not  identi- 
cal. The  ileo-colic  splits  into  two  of  which  the  lower  joins  the  last 
of  the  intestini  tenuis  and  the  upper  the  lower  of  the  two  from 
the  colioa  dextra  which  divides  into  two,  the  lower  to  the  ileo- 
colio  and  the  upper  the  right  branch  of  the  colica  medM,  whose 
left  branch  joins  the  upper  branch  of  the  colica  sinistra,  a  branch 
of  the  inferior  mesenteric.  No  secondary  loops  are  formed  from 
these  anastomoses  but  straight  branches  are  at  once  given  off  to 
the  large  intestines. 

The  Inferior  Mesenteric 

The  inferior  mesenteric,  much  smaller  than  the  su- 
perior, arises  near  the  termination  of  the  aorta  on  its 
left  side.  It  passes  to  the  left,  behind  the  peritoneum, 
gives  off  a  colica  sinistra  whose  upper  branch  passes  to 
the  right  to  meet  the  colica  dextra  on  the  transverse 
colon,  while  the  lower  passes  to  the  descending  colon  and 
anastomoses  with  the  highest  sigmoid  branches.  The 
sigmoidea  are  several  branches  the  highest  inosculating 
with  the  lower  of  the  sinistra,  the  lowest  with  the  superior 
hemorrhoidal  and  supplying  the  sigmoid  flexure. 

^The  superior  hemorrhoidal  is  the  termination  of  the 
inferior  mesenteric  and  supplies  the  upper  part  of  the 
rectum  and  anastomoses  with  hemorrhodial  branches 
from  the  internal  iliac. 

Summary 

The  abdominal  alimentary  canal  is  supplied  with  blood 
as  follows:  The  stomach  and  duodenum  by  the  gastric 
and  branches  from  the  hepatic  and  splenic  and  superior 
mesenteric ;  the  jejunum  and  most  of  the  ileum  by  the 
vasa  intestini  tenuis ;  the  lower  part  of  the  colon  and  up 
to  the  middle  of  the  transverse  colon  by  the  branches 
from  the  right  side  of  the  superior  mesenteric,  and 


118  ANATOMY   FOR   NURSES 

the  remainder  to  the  lower  part  of  the  rectum,  by  the 
inferior  mesenteric. 


THE  PORTAL  CIRCULATION 

Each  of  the  arteries  described  above,  except  the  he- 
patic, is  accompanied  by  a  vein  of  the  same  name, 
formed  by  veinlets  which  ramify  in  the  corresponding 
organs.  The  inferior  mesenteric  vein  empties  into  the 
superior;  the  superior  joins  the  splenic  to  form  the 
portal ;  the  gastric  veins  join  the  splenic  before  it  reaches 
the  superior  mesenteric. 

The  portal  vein,  therefore,  receives  blood  which 
comes  from  the  abdominal  intestinal  tract  from  the  be- 
ginning of  the  stomach  to  the  middle  of  the  rectum  in- 
clusive. This  embraces  all  the  digestive  tract,  the 
spleen,  and  the  pancreas.  This  blood,  charged  with  the 
products  of  digestion  in  addition  to  the  ordinary  con- 
tents of  venous  blood,  enters  the  liver  with  the  hepatic 
artery,  breaks  up  into  branches  of  ever  diminishing  size 
to  ramify  throughout  that  organ  and  then  form  vein- 
lets  which  collect  the  blood  again  until  they  unite  to 
form  the  hepatic  veins  which  ultimately  pour  this  great 
volume  of  blood  intoHi^  inferior  vena  cava  just  before 
it  emp%ies--mtG  4he  -heart.  \JO^»JL  < 

THE  GENITO-URINARY  ARTERIES 

These  vessels  are  the  renal,  suprarenal  and  spermatic 
or  ovarian. 

The  renal  arteries  are  short  large  vessels,  the  right 
the  larger,  which  pass  outward  to  the  hilum  of  the  kid- 
ney, one  on  each  side,  where  they  break  up  into  three 


ARTERIES    AND   VEINS  119 

branches,  one  to  each  third  of  the  organ.    They  lie  be-^ 
hind  the  peritoneum  with  the  renal  vein  in  front  and 
the  ureter  behind. 

The  suprarenals  are  small  wigs,  often  springing  from 
the  renal,  for  the  suprarenal  gland. 

The  spermatic  is  a  long  slender  vessel  rising  just  be- 
low the  renal  which  leaves  the  abdomen  through  the 
inguinal  canal,  with,  other  elements  of  the  spermatic 
cord,  and  is  distributed  to  the  testicle. 

The  ovarian  arteries  are  analogous  to  the  spermatic. 
They  pass  over  the  beginning  of  the  external  iliac  ar- 
try,  run  in  the  folds  of  the  broad  ligament  and  are  dis- 
tributed to  the  ovaries. 

ARTERIES  OF  THE  HEAD  AND  NECK 

Three  branches  spring  from  the  top  of  the  transverse 
aorta,  innominate,  left  common  carotid,  arid  left  sub- 
clavian.  The  innominate  combines  the  right  common 
carotid  and  subclavian. 

The  Innominate  Artery 

The  vessel  springs  from  the  beginning  of  the  trans- 
verse aorta  and  passes  upward  and  to  the  right  through 
the  superior  mediastinum  to  the  sterno-clavicular  ar- 
ticulation where  it  divides  into  the  right  common  carotid 
and  right  subclavian  arteries.  On  its  outer  side  is  its 
own  vein,  across  its  front  the  left  innominate  vein,  inter- 
nally the  left  common  carotid  and,  behind  and  inter- 
nal, the  trachea.  The  right  lung  and  pleura  ovelap  it. 

The  Left  Common  Carotid 

This  artery  lies  with  the  innominate  on  its  right  and 
left  subclavian  on  its  left  and  slightly  behind.  It  is 


120  ANATOMY    FOR    NURSES 

crossed  by  the  left  innominate  vein,  has  the  trachea  and 
esophagus  behind  and  internal,  the  left  pneumogastric 
and  phrenic  nerves  to  its  outer  side,  and  the  recurrent 
laryngeal  first  behind  and  then  internal.  Its  thoracic 
portion  stops  at  the  sterno-clavicular  articulation  and 
the  cervical  portion,  which  is  like  the  right,  needs  no 
description. 

The  Left  Subclavian 

The  thoracic  portion  of  the  left  subclavian  extends 
from  near  the  end  of  the  transverse  aorta  to  the  inner 
border  of  the  scalenus  anticus  muscle.  It  is  nearly  in- 
vested by  the  left  pleura  and  lung.  The  left  carotid  is 
internal,  the  left  innominate  vein  crosses  in  front  high 
up,  the  phrenic  nerve  is  in  front,  the  pneumogastric  an- 
tero-internal  and  the  thoracic  duct  behind  and  internal. 

The  last  three  vessels  are  behind  the  sternum  and  are 
in  relation  with  the  structures  attached  to  that  bone. 

The  Cervical  Carotids 

The  common  carotids  in  the  neck  lie  on  the  group  of 
muscles  covering  the  transverse  processes  as  high  as  the 
fourth,  on  a  level  with  the  upper  border  of  the  thyroid 
cartilage,  where  they  divide  into  internal  and  external 
carotids.  They  are  in  a  sheath  formed  by  the  deep  cer- 
vical fascia,  in  which  are  the  internal  jugular  vein  and 
the  pneumogastric  nerve.  They  are  deeply  seated  at 
the  root  of  the  neck  where  they  are  covered  by  the 
muscles  attached  to  the  sternum,  but  become  more  su- 
perficial as  the  muscles  draw  away  above.  The  pla- 
tysma,  deep  cervical,  fascia,  and  skin  cover  them 
throughout.  The  sterno-cleido-mastoid  covers  them  be- 
low and  overlaps  them  above.  Its  inner  border  is  the 


ARTERIES   AND   VEINS  121 

guide  to  the  vessels.  The  internal  jugular  vein  is  ex- 
ternal, the  pneumogastric  nerve  between  artery  and 
vein,  descendens  hypoglossi  on  the  front  of  the  sheath, 
and  the  cervical  sympathetic  behind  it.  Internally  are 
the  larynx,  above,  and  trachea  below.  No  branches 
arise  from  these  vessels. 

The  External  Carotid 

The  external  carotid  is  the  smaller  of  the  terminal 
branches  of  the  common  carotid.  Beginning  at  the  up- 
per border  of  the  thyroid  cartilage  it  terminates  'be- 
hind the  neck  of  the  lower  jaw  by  dividing  into  the 
temporal  and  internal  maxillary.  It  is  covered  by  the 
skin,  fascia  and  platysma  and  overlapped,  at  first,  by 
the  sterno-mastoid.  The  digastric  muscle  crosses  its 
front  and  is  used  by  surgeons  to  divide  it  into  three 
parts.  It  is  crossed  by  the  twelfth  nerve  and  has  the 
ninth  nerve  and  superior  laryngeal  behind  it.  Its  upper 
part  is  imbedded  in  the  parotid  gland.  Internally  is 
the  pharynx. 

Branches. — These  are  seven  in  number,  superior  thyroid,  lin- 
gual, facial,  occipital,  posterior  auricular,  ascending  pharyng&al, 
and  parotidean.  Their  names  indicate  the  parts  supplied. 

The  superior  thyroid  goes  to  structures  around  the  thyroid  car- 
tilage and  inosculates  with  its  fellow  of  the  opposite  side  and  with 
an  inferior  thyroid  from  the  subclavian. 

The  lingual  goes  to  muscles  attached  to  the  hyoid  bone,  but 
chiefly  to  the  tongue. 

The  facial  gives  large  branches  below  the  lower  jaw,  runs 
tortuously  across  the  face  from  an  inch  in  front  of  the  angle 
of  the  jaw,  where  its  pulsation  can  be  felt,  to  the  inner  angle  of 
the  eye  where  it  inosculates  with  a  branch  from  the  internal 
carotid.  It  supplies  the  chin,  lips,  cheeks,  and  nose  in  part. 

The  occipital  winds  beneath  the  mastoid  process  of  the  tem- 
poral to  reach  the  back  of  the  skull  where  it  inosculates  with 


122  ANATOMY   FOR   NURSES 

its  fellow  of  the  opposite  side  and,  in  front,  with  the  posterior 
temporal.  It  supplies  the  back  part  of  the  scalp  and  gives  one 
large  muscular  branch  in  the  neck  (princeps  cervicis)  which  runs 
downward  and  establishes  a  communication  with  a  branch  of  the 
subclavian. 

The  posterior  auricular  is  distributed  to  the  back  of  the  ear. 

The  pafotidean  are  four  or  five  small  branches  for  the  parotid 
gland. 

The  a-scending  pliaryngeal,  coming  off  near  the  origin  of  the 
carotid,  passes  up  the  neck  to  the  pharynx  and  by  one  branch, 
to  the  membrane  of  the  brain. 

The  Temporal  Artery 

The  temporal  is  the  smaller  of  the  terminal  branches 
of  the  carotid.  It  mounts  over  the  zygoma  and  gives 
off  branches  which  supply  the  front  of  the  ear,  the  side 
of  the  face,  the  temporal  muscle  and  the  middle  por- 
tion of  the  scalp,  inosculating  in  front  with  the  frontal, 
derived  from  the  internal  carotid,  and  behind  with  the 
occipital. 

The  Internal  Maxillary 

The  internal  maxillary,  much  larger  than  the  tem- 
poral, turns  inward  and  forward  from  the  neck  of  the 
lower  jaw  to  run  finally  into  the  space  between  the 
sphenoid  and  superior  maxilla.  Its  work  is  to  supply 
the  deep  structures  of  the  face,  including  the  teeth, 
and  the  membranes  of  the  brain. 

Branches. — A  small  branch  enters  the  ear  while  a  much  larger, 
meningea  media,  passes  to  the  middle  fossa  of  the  skull  through 
a  hole  in  the  sphenoid,  and,  ramifying  between  the  bone  and  dura, 
grooving  the  bones  deeply,  is  the  chief  artery  of  the  dura. 

The  inferior  dental  runs  in  a  tunnel  in  the  lower  jaw  and  gives 
a  branch  to  every  fang  of  every  tooth  as  it  passes,  finally  emerg- 
ing on  the  chin  to  inosculate  with  the  facial. 

The  muscular  branches  are  distributed  to  the  muscles  of  mas- 
tication. 


ARTERIES   AND   VEINS  123 

Superior  dental  brandies  supply  the  teeth  of  the  upper  jaw, 
while  an  infraorbital  emerges  from  a  tunnel  beneath  the  floor  of 
the  orbit  to  appear  on  the  face  and  communicate  with  the  facial. 
Other  branches  supply  the  palate,  nose,  pharynx  and  eustachian 
tube. 

.  The  face  is  very  abundantly  supplied  with  blood.  Arteries 
come  to  it  from  various  sources  and  inosculate  with  great  free- 
dom. It  is  nearly  impossible  to  cut  off  collateral  circulation1  and 
these  tissues  will  survive  injuries  which  would  destroy  many 
others. 

The  Internal  Carotid 

The  internal  carotid  continues  the  course  of  the  com- 
mon carotid  upward  to  the  base  of  the  skull  where  it 
enters  a  foramen  in  the  petrous  part  of  the  temporal 
bone,  runs  forward  and  inward  in  a  tunnel  in  that 
bone,  turns  upward  in  the  middle  fossa  of  the  skull  and 
terminates  by  dividing  into  an  anterior  and  middle  cere- 
bral, posterior  communicating  and  anterior  choroid. 

This  vessel  is  deeply  seated  and  in  relation  with  many 
important  structures,  very  important  to  the  surgeon 
but  of  little  use  to  the  nurse.  The  internal  jugular 
vein  lies  on  its  outer  side,  the  tenth  nerve  lies  between 
vein  and  artery  and  the  ninth,  eleventh  and  twelfth 
nerves  all  bear  relations  to  it.  The  sympathetic  is 
behind. 

Branches. — The  distribution  of  these  is  largely  to  the  brain 
and  can  not  be  comprehended  until  the  brain  is  studied. 

The  ophthalmic  is  distributed  to  structures  in  and  around  the 
orbit.  It  comes  off  near  the  end  of  the  artery,  enters  the  oroit 
through  the  optic  foramen  and  breaks  up  into  nearly  a  dozen 
branches.  These  are  distributed  to  the  eyeball  (cMiary},  retina, 
eyelids  (palpebral) ,  lachrymal  gland,  nasal  cavity  and  ethmoidal 
cell  while  two  branches,  the  supraorbital  and  frontal  pass  out  of 
the  orbit  to  the  front  of  the  scalp  which  they  nourish  and  where 


124  ANATOMY   FOR    NURSES 

they  communicate  with  the  temporal,  with  each  other  and  with 
the  vessels  of  the  opposite  side. 


ARTERIES  OF  THE  UPPER  EXTREMITY 

The  Subclavian 

The  cervical  subclavian  extends  on  the  right  from  the 
bifurcation  of  the  innominate  at  the  sterno-clavicular 
joint  to  the  outer  border  of  the  first  rib;  on  the  left 
from  the  inner  edges  of  the  scalenus  anticus  to  the  outer 
border  of  'the  left  first  rib. 

The  first  and  second  parts  of  the  right  subclavian  are 
deeply  seated,  covered  by  skin,  fascia,  platysma,  sterno- 
mastoid,  while  the  outer  third  of  each  is  superficial, 
having  only  skin,  fascia  and  platysma  as  coverings. 
The  apex  of  the  lung  is  under  the  subclavian  in  its  first 
two  parts.  The  pneumogastric  and  phrenic  nerves 
cross  it  in  front  with  the  internal  jugular  vein,  which 
unites  with  the  subclavian  to  form  the  right  innomi- 
nate. The  artery  is  bent  like  a  bow;  the  vein  runs 
straight  and  only  touches  the  artery  at  its  inner  and 
outer  ends.  The  recurrent  laryngeal  nerve  winds  from 
front  to  back.  The  brachial  plexus  of  nerves  comes  in 
contact  with  the  artery  in  its  second  part  and  lies 
above  and  somewhat  posterior. 

Branches. — These  are  the  vertebral,  thyroid  axis  breaking  into 
the  inferior  thyroid,  suprascapular  and  transverse  cervical;  the 
internal  mammary,  superior  intercostal  and  profunda  cervicis. 

The  vertebral  enters  the  foramen  in  the  transverse  process  of 
the  sixth  cervical,  passes  through  these  foramina  in  succession, 
giving  off  branches  to  the  spinal  canal  and  its  contents,  enters 
the  skull  through  the  foramen  magnum  and  joins  the  opposite 
vertebral  to  form  the  basilar  whose  distribution  is  taken  up  with 
the  arteries  of  the  brain. 


ARTERIES   AND   VEINS  125 

The  inferior  thyroid  is  distributed  to  the  thyroid  gland  and 
muscles  of  the  neck,  inosculating  with  the  superior  thyroid  and 
the  opposite  artery. 

The  suprascapular  passes  outward  across  the  third  part  of  the 
subclavian,  accompanied  by  its  vein,  and  \&  distributed  in  the 
supraspinous  and  infraspinous  fossae. 

The  transverse  colli  runs  across  the  neck  and  breaks  into  two 
branches,  the  upper  to  anastomose  with  the  occipital  and  the 
lower  to  run  along  the  vertebral  border  of  the  scapula,  com- 
municating with  the  suprascapular  and  subscapular. 

The  internal  mammary  runs  down  the  thorax  behind  the  costal 
cartilages  about  half  an  inch  from  the  sternum  to  the  diaphragm 
where  it  divides  into  the  superior  epigastric  and  musoulo-phrenic. 
It  gives  off  anterior  intercostals  to  the  intercostal  spaces,  a 
branch  to  the  phrenic  nerve,  mediastinal  and  pericardiac  and  six 
anterior  perforating  branches  which  run  between  the  ribs  to 
the  muscles  of  the  chest  and  the  mammary  gland.  They  are 
larger  and  more  important  in  the  female  than,  in  the  male. 

The  superior  epigastric  passes  down  in  the  rectus  muscle  to 
inosculate  with  an  inferior  epigastric  of  the  external  iliac. 

The  inusculo-phrenic  gives  off  intercostal  branches  to  the  lower 
spaces  and  muscular  branches  to  the  diaphragm. 

The  superior  intercostal  and  profunda  cervicis  usually  rise  by 
a  common  trunk,  the  former  supplying  the  first  intercostal  space 
and  the  latter  anastomosing  with  a  Branch  of  the  occipital. 

The  Axillary 

The  axillary  begins  behind  the  outer  third  of  the 
clavicle,  on  the  outer  border  of  the  first  rib,  as  a  contin- 
uation of  the  subclavian,  and  passes  through  the  outer 
angle  of  the  axilla  to  become  the  brachial  at  the  lower 
border  of  the  teres  major. 

It  is  covered  by  the  pectoral  muscles,  rests  on  the  sub- 
scapularis  and  tendons  of  the  latissimus  dorsi  and  teres 
major,  has  the  serratus  magnus  internal  and  the  short 
head  of  the  biceps  and  the  coraco-brachialis  external 
for  the  lower  part.  The  axillary  vein  is  internal  and  in 
front  throughout.  The  brachial  plexus  lies  external 


126  ANATOMY   FOR    NURSES 

and  behind  at  first,  breaks  into  three  cords  which  lie 
behind,  external  and  internal  behind  the  pectoralis 
minor  and  gives  off  its  terminal  branches  which  surround 
the  artery  just  below  that  muscle  and  then  lie  on  three 
sides,  inner,  outer,  and  posterior. 

Branches. — These  are  very  irregular.  One,  superior  thoracic, 
supplies  the  pectoral  muscles;  one,  acromial  thoracic,  the  deltoid 
and  other  structures  around  the  acromion.  The  long  thoracic 
goes  to  the  chest  wall  and  the  alar  thoracic  to  the  structures  in 
the  axilla. 

The  anterior  and  posterior  circumflex,  the  latter  much  the 
larger,  surround  the  surgical  neck  of  the  humerus  and  supply  it, 
the  deltoid,  and  the  shoulder. 

The  subscapular,  the  largest  branch,  supplies  the  subscapular 
fossa,  part  of  the  inf raspinous  and  the  muscles  attached  to  these 
and  the  axillary  border  of  the  scapula. 

The  Axilla 

This  is  a  wedge-shaped  space  between  the  upper  five 
ribs  internally,  the  bicipital  groove  of  the  humerus  ex- 
ternally and  the  scapula  behind.  Its  apex  is  above. 
The  pectoral  muscles  form  its  anterior  wall,  the  serra- 
tus  magnus  the  internal  and  the  subscapularis  teres 
major  and  latissimus  dorsi  its  posterior.  The  outer 
angle  ends  in  the  bicipital  groove  between  the  anterior 
and  posterior  walls.  The  floor  is  formed  by  the  invest- 
ing fascia  stretching  from  the  anterior  to  the  posterior 
folds.  The  outer  angle  is  filled  by  the  axillary  vessels, 
nerves,  and  lymphatics,  which  follow  the  course  of  the 
vessels,  while  the  inner  and  lower  part  contains  a  con- 
siderable amount  of  fat. 

The  Brachial 

The  brachial  is  a  continuation  of  the  axillary  and 
terminates  a  ' '  fingersbreadth ' '  below  the  bend  of  the 


Axillary  artery  and  vein 


V.  cephalic — 


A.  radical — 
A.  and  V.  post,  interosseous — 


A.  anastomotica  magna 


Princeps  pollicis — 


A.  and  V.  post,  circumflex 
.  and  V.  ant.  circumflex 


— A.  ulna 

— A.  and  V.  ant.  interosseous 


Sup.  palmar  arch 


-Palmar  collateral  digital 
Fig.    15. — Diagram  of  arteries  and  veins  of  upper  extremity. 


ARTERIES   AND   VEINS  127 

elbow  by  dividing  into  radial  and  ulnar.  It  is  super- 
ficial, covered  only  by  skin,  superficial  and  deep  fas- 
cias,  overlapped  by  the  biceps  from  the  outer  side  and 
easily  compressed  against  the  bone  outward  and  back- 
ward above,  and  backward  below.  Unlike  the  corre- 
sponding vessel  of  the  lower  extremity  (popliteal)  it 
has  satellite  veins,  one  on  each  side.  The  median  nerve 
is  first  external,  then  in  front  and  finally  internal.  The 
basilic  vein  and  internal  cutaneous  nerve  are  in  the  fas- 
cia which  covers  it  antero-internally. 

Branches. — The  superior  profunda  winds  through  the  musculo- 
spinal  groove  to  supply  muscles  on  the  back  of  the  arm  and  aid 
in  the  vascular  circle  around  the  elbow. 

The  inferior  profunda  passes  to  the  inner  side  of  the  elbow. 

The  anastomotica  magna  runs  transversely  around  three-quar- 
ters of  the  joint  from  the  inner  side,  and  is  the  chief  agent  in 
forming  the  anastomoses.  Muscular  branches  are  also  given  off. 

The  Radial 

The  radial  runs  down  the  outer  side  of  the  forearm  to 
the  styloid  process  where  it  turns  backward  across  the 
carpus  to  the  first  interosseous  muscle  through  which  it 
plunges  to  form  the  deep  palmar  arch. 

The  brachio-radialis  muscle  lies  external  to  this 
artery  and  is  the  guide  to  it.  Internally  the  flexor  carpi 
radialis  is  the  chief  relation.  Between  the  two  the 
lower  part  is  superficial  and  is  the  artery  most  fre- 
quently used  to  feel  the  pulse.  The  artery  has  satellite 
veins  and  the  nerve  is  external  in  the  middle. 

Branches. — A  recurrent  branch  aids  in  the  anastomoses  around 
the  elbow.  Muscular  twigs  supply  the  outer  side  of  the  forearm. 


128  ANATOMY   FOR   NURSES 

The  Ulnar 

The  ulnar  is  larger  than  the  radial  and  more  deeply 
seated.  It  runs  under  the  muscles  of  the  superficial 
group,  except  one,  flexor  carpi  ulnaris,  which  lies  to  its 
inner  side,  and  enters  the  palm  to  the  outer  side  of  the 
pisiform  to  form  the  superficial  palmar  arch.  It,  too, 
has  satellite  veins  and  its  nerve  internal  for  its  lower 
two-thirds. 

Branches. — Two  recurrent  branches  enter  the  elbow  circle. 

The  interosseous  is  a  short  trunk  breaking  into  a  large  anterior 
and  a  small  posterior  interosseous.  The  anterior  descends  on  the 
interosseous  membrane,  supplying  muscles  in  its  course,  and, 
piercing  the  membrane  below,  aids  in  forming  the  carpal  arch. 
The  posterior  passes  above  the  interosseous  membrane  and  is 
mainly  a  muscular  vessel  for  the  back  of  the  forearm,  but  a 
twig  gets  to  the  carpal  arch. 

Arterial  Supply  of  the  Hand 

Draw  a  line  from  the  top  of  the  web  between  thumb 
and  index  finger  and  the  superficial  palmer  arch  is 
roughly  represented.  This  is  formed  by  the  continua- 
tion of  the  ulnar  joining  a  branch  of  the  radial.  It  lies 
on  the  flexor  tendons  and  ulnar  and  median  nerves. 
From  the  arch  thus  formed  branches  pass  to  the  clefts 
between  the  fingers  and  divide  into  a  branch  for  the 
adjacent  sides  of  the  fingers.  These  are  called  palmar 
collateral  digital  branches  and  not  only  anastomose  with 
the  branch  of  the  opposite  side  of  the  finger,  but  with 
those  on  the  back  as  well.  The  branch  to  the  thumb 
comes  entirely  from  the  radial  and  is  called  princeps 
pollicis. 

The  deep  arch  lies  higher  up  on  the  carpus  and  under 
the  tendons.  It  is  formed  chiefly  by  the  radial  with  a 


ARTERIES    AND    VEINS  129 

communication  from  the  nlnar.  Its  branches  go  to  the 
carpus,  perforate  the  spaces  to  pass  to  the  back  of  the 
metacarpus,  and  give  interosseous  branches  which  join 
the  palmar  digital. 

A  posterior  carpal  arch  is  formed  by  small  branches 
from  the  radial  and  ulnar  and  this  with  three  branches, 
dorsales  pollicis  and  dorsalis  indicis  supply  branches  to 
the  back  of  the  hand  and  fingers. 


ARTERIES  OF  THE  PELVIS  AND  LOWER 
EXTREMITY 

Common  Iliac 

The  common  iliac  arteries  are  terminal  branches  of 
the  abdominal  aorta,  beginning  on  the  fourth  lumbar 
vertebra  and  diverging  to  reach  the  disc  between  the1 
fifth  lumbar  and  sacrum  wThere  they  bifurcate  to  form 
the  external  and  internal  iliac  arteries. 

These  vessels  lie  behind  the  peritoneum  and  viscera, 
and  each  vein  is  right  of  its  own  artery,  but  the  left  vein 
crosses  behind  the  right  artery  in  order  to  join  the 
right  vein  and  form  the  inferior  cava. 

There  are  no  branches. 

The  Internal  Iliac 


The  raternal-iliac  carries  blood  to  the  walls  and  vis- 
cera of  the  pelvis.  It  drops  over  the  pelvic  brim,  runs 
down  on  the  sacro-iliac  joint  to  the  sacro-sciatic  notch 
and  divides  there  into  an  anterior  and  posterior  trunk. 
It  lies  behind  the  peritoneum  with  the  ureter  in  front 
and  the  lumbosacral  cord  behind. 


130  ANATOMY   FOR    NURSES 

Branches. — From  the  anterior  trunk  come  branches  for  the 
bladder  (vesical)  and  rectum  (heniorrhoidal)  an  obturator  and 
two  terminal  branches,  internal  pudic  and  ischiatic,  and,  in  the 
female,  uterine  and  vaginal  branches. 

The  uterine  passes  to  the  neck  of  the  uterus,  runs  up  on  the 
side  and  joins  the  ovarian  artery.  The  vaginal  takes  the  place 
of  the  inferior  vesical  in  the  male. 

The  obturator  crosses  the  pelvic  wall,  with  its  nerve  above  and 
vein  below,  to  the  upper  part  of  the  obturator  foramen  through 
which  it  leaves  the  pelvis  to  be  distributed  to  muscles  of  the 
gluteal  and  adductor  groups  and  to  the  hip  joint. 

The  ischiatic  leaves  the  pelvis  through  the  great  sacro-sciatic 
foramen  and  runs  down  the  back  of  the  thigh  as  far  as  the  knee, 
giving  off  branches  to  muscles  of  that  region. 

The  internal  pudic,  or  pudendal,  artery  leaves  the  pelvis  through 
the  great  sacro-sciatic  foramen  to  reenter  through  the  lesser, 
run  along  the  ischio-pubic  rami  and  end  in  the  external  genital 
organs.  It  gives  a  branch  to  the  skin  of  the  perineum,  one  to  the 
back  of  the  penis,  one  to  the  carpus  spongiosum  and  one  to  the 
cavernosum.  In  the  female  these  branches  are  very  small  and 
go  to  analogous  parts. 

The  posterior  trunk  gives  off  the  ilio-lumbar  which  does  the 
work  of  a  lumbar  artery  and  in  addition,  supplies  the  iliac  fossa ; 
a  lateral  sacral,  which  gives  a  branch  to  each  anterior  sacra] 
foramen  and  terminates  in  the  gluteal,  a  large  artery  which 
leaves  the  pelvis  above  the  pyriformis,  supplies  muscles  of  the 
gluteal  region  and  aids  in  forming  the  anastomoses  around  the 
hip  joint. 

The  External  Iliac 

The  external  iliac  begins  at  the  fifth  lumbar  disc  and 
terminates  under  the  middle  of  Poupart's  ligament  by 
changing  its  name  to  femoral.  It  is  behind  the  peri- 
toneum, has  its  vein  internal,  the  psoas  magnus  external 
and  the  ovarian  artery  in  front,  in  the  female,  on  both 
sides.  The  right  is  overlapped  by  the  cecum  and  often 
crossed  by  the  appendix.  The  left  has  the  sigmoid 
flexure  lying  on  it. 


A.  sup.  ext.  articular 
A.  inf.  ext.  articular — i 

! 

A.  ant.  recurrent  tibial — 1 


' — A.  femoral 

-A.  profunda  femoris 

-A.  internal  circumflex 

— A.  external  circumflex 


-A.  first  perforating 


-A.  second  perforating 


-A.  third  perforating 
-A.  anastomotica  magna 


-A.  popliteal 

-A.  sup.  internal  articular 

| 
I 
* — A.  inf.  int.  articular 


-A.  ant.  tibial 
-A.  post,  tibial 

— A.  peroneal 


A.  ant.  peroneal — 
A.  ext.  malleolar — 

A. A.  ext.  calcaneal — | 
A.  ext.  plantar- 


— A.  int.  malleolar 

FA.A.  int.  calcaneal 
— A.  dorsalis  pedis 
I — A.  int.  plantar 


— A.  metatarsal 
A.  communicating 


Fig.  16. — Diagram  of  arterial  circulation  in  lower  extremity. 


•Bi.r.-n.nV 


ARTERIES    AND   VEINS  131 


Branches. — These  are  two,  deep  epigastric  and  deep  circum- 
//( ./•  iliac. 

The  deep  epigastric  runs  upward  in  the  sheath  of  the  rectus, 
gives  off  muscular  branches,  and  anastomoses  with  the  internal 
mammary. 

The  deep  circumflex  iliac  courses  along  Poupart's  ligament  and 
the  crest  of  the  ilium,  gives  branches  to  the  broad  muscles  and 
anastomoses  with  the  lumbar  and  gluteal  arteries. 

The  Femoral 

The  femoral  runs  from  a  point  midway  between  the 
anterior  superior  spine  of  the  ilium  and  the  symphysis 
pubis  across  the  front  and  inner  side  of  the  thigh  to 
its  lower  third,  where  it  turns  to  the  back  and  becomes 
the  popliteal.  It  is  superficial  above,  lying  in  a  space, 
Scarpa's  triangle,  bounded  above  by  Poupart's  liga- 
ment, externally  by  the  sartorius  internally  by  the  ad- 
ductor behind.  Its  vein  is  internal  and  abreast  at  first 
but  gets  longer  and  then  external.  The  anterior 
femoral  nerve  is  a  quarter  of  an  inch  to  its  outer  side. 
Two  inches  below  its  origin  it  gives  off  from  its  outer 
side,  the  profunda  femoris  which  quickly  gets  behind 
with  its  own  vein  in  front  of  it.  So  that  femoral  artery, 
femoral  vein,  profunda  vein,  profunda  artery  would  be 
the  order  from  before  backward. 

Branches. — Besides  several  superficial  branches  to  the  pubic 
region,  lower  abdomen,  space  around  the  anterior  spine  of  the 
ilium,  and  muscular  branches,  this  artery  gives  off  the  anasto- 
motica  magna  at  its  lower  portion  to  partly  encircle  the  femur 
and  form  a  great  portion  of  the  vascular  zone  around  the  knee 
joint. 

The  profunda  femoris  carries  the  greater  part  of  the 
blood  of  the  thigh.  It  gives  off  external  and  internal 
circumflex  branches,  the  external  the  larger,  which  en- 


132  ANATOMY   FOB   NURSES 

circle  the  upper  part  of  the  femur,  aid  greatly  in  the 
anastomoses  around  the  hip  joint  and  supply  muscles 
of  the  thigh. 

The  three  perforating  arteries  come  from  the  profunda 
on  the  adductor  muscles,  which  they  perforate  to  appear 
at  the  back  of  the  thigh. 

The  Popliteal 

The  popliteal  extends  from  the  lower  third  of  the 
femur,  across  the  back  of  the  knee  joint,  to  the  upper 
fifth  of  the  tibia  where  it  divides  into  anterior  and  pos- 
terior tibial  arteries.  It  lies  on  the  femur,  posterior  lig- 
ament of  the  knee  and  popliteus  muscle  and  is  sur- 
rounded by  the  muscles  bounding  the  popliteal  space. 
Its  vein,  which  hugs  the  artery  closely,  is  behind  and 
the  internal  popliteal  nerve  is  behind  the  vein.  They 
cross  the  artery  obliquely  and  are  a  little  external 
above  and  a  little  internal  below. 

Branches. — Muscular  branches,  above  and  below  the  joint,  are 
given  to  the  hamstring  muscles  and  heads  of  the  gastrocnemius, 
besides  five  articular  arteries,  two  above,  two  below,  and  one  in 
the  middle,  supplying  the  joint.  They  communicate  with  each 
other,  the  anastomotica  magna  and  recurrent  branches  from  the 
tibia. 

The  Anterior  Tibial 

The  anterior  tibial  passes  between  the  leg  bones  and 
runs  down  the  interosseous  membrane,  between  mus- 
cles of  the  anterior  group  to  the  middle  of  the  ankle, 
beneath  the  annular  ligament,  where  it  changes  its 
name  to  dorsalis  pedis  which  continues  the  artery  to  the 
base  of  the  big  toe. 

It  is  accompanied  by  satellite  veins  and  its  nerve  which 
is  antero-external. 


ARTERIES    AND   VEINS  133 

Branches. — A  recurrent  branch  joins  the  knee  circle.  Muscular 
branches  supply  the  tibial  group,  and  external  and  internal  mal- 
leolar  form  a  large  part  of  the  ankle  circle. 

The  Posterior  Tibial 

The  posterior  tibial,  larger  than  the  anterior,  runs 
down  between  the  deep  and  superficial  groups  on  the 
back  of  the  leg  to  midway  between  the  inner  malleolus 
and  the  heel  where  it  divides  into  the  internal  and  ex- 
ternal plantar  arteries.  It  is  accompanied  by  satellite 
veins  and  its  nerve  which  is  internal  at  first  but  quickly 
crosses  it  behind  to  remain  external  to  the  end.  At  the 
ankle  it  lies  between  the  tendon  of  the  flexor  longus 
digitorum  internally  and  the  longus  pollicis  externally. 

Branches. — Besides  muscular  and  internal  calcanean,  distrib- 
uted around  the  inner  aspect  of  the  heel  and  ankle,  it  gives  a 
large  branch  high  up  called  peroneal. 

The  peroneal  corresponds  to  the  posterior  interosseous  of  the 
uliiar.  It  descends  to  the  lower  part  of  the  leg,  gives  off  a  large 
anterior  peroneal  branch  and  itself  runs  to  the  outer  side  of  the 
heel  as  the  external  calcanean. 

Arterial  Supply  of  the  Ankle  and  Foot 

The  malleolar  and  calcanean  arteries  communicate 
with  each  other  and  with  branches  of  the  plantar  and 
dorsalis  pedis  arteries  to  form  the  annular  zone  around 
the  ankle.  /  . 

The  e^^Safplantar  artery  corresponds  to  the  super- 
ficial palmar  arch,  supplies  the  three  and  a  half  outer 
toes  and  anastomoses  with  a  communicating  branch  of 
the  dorsalis  pedis,  which  supplies  the  big  toe  and  inner 
half  of  the  second. 

The  ifiecteS  plantar  is  chiefly  a  muscular  branch  for 
the  inner  part  of  the  sole. 


134  ANATOMY    FOR    NURSES 

The  dorsalis  pedis  supplies  the  back  of  the  great  toe 
and  half  the  second.  The  remaining  toes  are  supplied 
dorsally  by  interosseous  branches  from  the  metatarsal 
branch  of  the  dorsalis  pedis. 

THE  VEINS 

The  veins  are  divided  into  superficial,  lying  in  the  su- 
perficial fascia,  and  deep,  accompanying  the  arteries. 
Some  channels  in  the  skull,  called  sinuses,  perform  the 
functions  of  veins. 


THE  VEINS  OF  THE  LOWER  EXTREMITY 

The  superficial  veins  of  the  lower  extremity  are  the 
long  and  short  sapheiious.  They  are  abundantly  pro- 
vided with  valves  which  enable  the  vertical  columns  of 
blood  to  overcome  gravity. 

The  Long  Saphenous 

Just  back  of  the  web  of  the  toes  a  venous  arch  is 
formed  across  the  dorsum  of  the  foot  which  receives 
tributaries  from  the  toes  and  gives  rise  to  the  long 
saphenous  vein  on  the  inner  side  of  the  foot.  It  runs 
across  the  front  of  the  inner  malleolus,  up  the  inner 
side  of  the  leg  to  the  back  of  the  inner  condyle,  re- 
ceives a  communication  from  the  short  saphenous,  con- 
tinues up  the  inner  face  of  the  thigh,  receiving  tribu- 
taries all  the  way,  reaches  the  saphenous  opening  in  the 
fascia  lata  Avhere  it  receives  the  veins  accompanying 
the  superficial  branches  of  the  femoral  artery,  and  emp- 
ties into  the  femoral  vein. 


ARTERIES    AND   VEINS  135 

The  Short  Saphenous 

The  short  saphenous  begins  at  the  outer  side  of  the 
dorsal  arch  passes  around  the  outer  malleolus  to  the 
calf,  up  the  middle  of  which  it  runs  to  the  popliteal 
space,  where,  after  giving  a  communication  to  the  long 
saphenous,  it  empties  into  the  popliteal  vein. 

Deep  Veins  of  the  Lower  Extremity 

Metatarsal  veins  unite  to  form  satellite  veins  for  the 
plantar  arteries.  The  two  inner  and  the  two  outer  plantar 
veins  unite  to  form  the  satellites  of  the  posterior  tibial, 
which  unite  with  those  of  the  anterior  tibial  to  form  the 
popliteal.  This  accompanies  the  popliteal  artery  to  the 
lower  third  of  the  thigh  where  it  becomes  the  femoral ; 
follows  that  artery  to  two  inches  below  Poupart's  liga- 
ment, where  it  receives  the  deep  femoral,  then  the  long 
saphenous  and  passes  under  Poupart's  ligament  to  be- 
come the  external  iliac. 

The  external  iliac  receives  the  epigastric  and  circum- 
flex iliac  veins  and  joins  the  internal  iliac  to  form  the 
common  iliac.  The  two  common  iliacs  unite  at  the 
fifth  lumbar  disk  on  the  right  side  and  form  the  inferior 
vena  cava  which  passes  through  the  diaphragm  op- 
posite the  ninth  dorsal  vertebra  and  empties  into  the 
right  auricle  of  the  heart. 

THE  VEINS  OF  THE  UPPER  EXTREMITY 

These  are  also  superficial  and  deep  and  are  provided 
with  valves.  The  deep  and  superficial  anastomose  fre- 
quently. 


136  ANATOMY    FOR    NURSES 

The  Superficial  Veins  of  the  Upper  Extremity 

A  network  of  veins  is  formed  on  both  surfaces  of  the 
hand,  though  more  apparent  on  the  back.  Near  the 
wrist  a  vein  called  median  begins  and  passes  up  the 
middle  of  the  front  of  the  forearm  until  just  below 
the  elbow  where  it  divides  into  the  median  cephalic 
exreraally  and  the  median  basilic  irri!ew*alr$  The  veins 
on  the  outer  side  of  the  hand  give  rise  to  a  superficial 
radial  vein  which  courses  up  the  outer  side  of  the 
forearm  to  join  the  median  cephalic  and  form  the 
cephalic.  This  vein  passes  up  the  outer  side  of  the 
arm,  runs  into  the  groove  between  the  deltoid  and 
pectoralis  major  muscles,  and  empties  into  the  axil- 
lary vein  just  below  the  clavicle. 

There  are  two  ulnar  veins  anterior  and  posterior 
which  run  up  the  front  and  back  of  the  inner  part  of 
the  forearm.  They  unite  to  form  the  common  ulnar  an 
inch  or  more  below  the  elbow  joint  and  this  joins  the 
median  basilic  to  form  the  basilic  vein.  The  basilic 
vein  runs  up  the  inner  side  of  the  arm,  pierces  the  in- 
vesting fascia  and  joins  the  brachial  satellites  (the  inner 
usually)  to  form  the  axillary. 

The  deep  veins  begin  as  satellites  of  the  superficial 
and  deep  arches,  receive  digital  and  metacarpal  veins, 
form  satellites  of  the  radial  and  ulnar  arteries  which  in 
turn,  after  the  ulnar  receives  the  interosseous  satellites, 
unite  to  form  the  brachial  satellites  which  either  unite 
and  join  the  basilic,  or  the  inner  joins  the  basilic  and 
receives  the  outer,  to  form  the  axillary. 

The  axillary  vein  accompanies  the  axillary  artery, 
receives  the  numerous  tributaries  which  follow 


ARTERIES    AND   VEINS  137 

branches  of  that  vessel,  is  joined  by  the  cephalic  just 
below  the  clavicle  and  becomes  the  subclavian. 

The  subclavian  vein  touches  its  artery  only  at  its 
ends.  It  receives  the  external  jugular  vein  in  addition 
to  the  veins  accompanying  the  branches  of  the  sub- 
clavian artery  and  also  the  thoracic  duct  on  the  left 
and  right  lymph  duct  on  the  right,  just  at  its  junction 
with  internal  jugular  to  form  the  innominate. 


THE  VEINS  OF  THE  HEAD  AND  NECK 

The  veins  of  the  brain  and  its  membranes  empty  into 
channels  in  the  dura  called  sinuses.  The  chief  sinuses 
are  the  superior  and  inferior  longitudinal,  the  straight, 
the  occipital,  lateral  and  petrosal.  Many  of  these  meet 
at  the  anterior  occipital  protuberance  and  pour  their 
blood  into  the  straight  sinuses  which  run  to  the  jugu- 
lar foramen  on  each  side  where  they  meet  the  in- 
ferior petrosal  sinuses,  one  on  each  side,  and  their 
junction  forms  the  internal  jugular  vein.  The  ophthal- 
mic veins  empty  into  the  cavernous  sinus  and  its  blood 
also  goes  to  the  jugular. 

The  anterior  facial  vein  is  formed  by  branches  from 
the  forehead,  nose,  lids,  lips,  and  cheeks.  It  runs 
across  the  lower  jaw  with  the  facial  artery,  receives  a 
communication  from  the  posterior  facial  and  empties 
into  the  internal  jugular  below  the  hyoid. 

The  external  jugular  is  formed  by  the  posterior  au- 
ricular and  posterior  facial.  The  first  comes  from  the 
back  of  the  ear;  the  second  is  formed  by  the  union  of 
the  superficial  temporal  and  internal  maxillary  and  is 
often  called  temporo-facial.  The  vein  grosses  the 


138  ANATOMY   FOR   NURSES 

sternor-mastoid,  running  downward  and  outward,  be- 
neath the  platysma  and  empties  into  the  subclaviaii 
vein  after  crossing  the  third  part  of  the  subclaviaii 
artery.  It  often  receives  the  transverse  cervical  and 
suprascapular  veins. 

The  internal  jugular  vein,  formed  by  the  lateral  and 
inferior  petrosal  sinuses,  accompanies  the  internal  and 
common  carotid  arteries,  enclosed  in  the  same  sheath, 
receives  tributaries  from  the  branches  of  the  external 
carotid  and  unites  with  the  subclavian  to  form  an  in- 
nominate vein. 

The  left  innominate,  great  transverse  vein,  is  larger 
than  the  right  lying  011  the  front  of  the  left  subclavian, 
left  carotid,  and  innominate  arteries.  The  two  unite 
at  the  termination  of  the  ascending  aorta  to  form  the 
superior  vena  cava  which  empties  into  the  right  auricle. 

The  vertebral  veins  are  a  plexus  surrounding  the  ver- 
tebral arteries  in  the  foramina  in  the  transverse  proc- 
esses. They  empty  into  the  innominate  veins,  which 
also  receive  the  inferior  thyroid  and  internal  mammary 
veins. 

Most  of  the  intercostal  veins  empty  into  the  great 
azygos,  a  vein  which  begins  in  the  abdominal  cavity 
and  passes  through  the  posterior  mediastinum  to  empty 
into  the  superior  cava.  Cardiac  blood  is  collected  by 
veins  accompanying  the  coronary  arteries  and  uniting 
in  the  coronary  sinus  which  empties  into  the  right 
auricle. 

THE  LYMPHATICS 

The  lymphatic  system  consists  of  numerous  minute 
vessels  ramifying  throughout  the  body  and  certain  small 


ARTERIES    AND    VEINS  139 

glandular  bodies  at  intervals  along  the  vessels.  They 
accompany  the  veins  and  are  arranged  in  chains,  notably 
in  the  groin,  axilla,  neck,  pelvis,  and  abdomen.  Many 
of  them  converge  to  form  an  irregular  sac,  the  receptac- 
ulum  chyli,  on  the  body  of  the  second  lumbar  vertebra. 
This  contracts  to  a  tube  about  the  size  of  a  wheat  straw 
which  accompanies  the  aorta  through  the  posterior  me- 
diastinum to  the  fourth  do**aY 'vertebra  where  it  passes 
behind  the  transverse  aorta  and,  bending  somewhat  for- 
ward opposite  the  interval  between  the  left  carotid  and 
subclavian  arteries,  runs  into  the  root  of  the  neck  and, 
crossing  the  subclavian,  empties  into  the  junction  of 
the  left  subclavian  and  internal  jugular  veins.  Just 
before  it  terminates  it  receives  the  left  duct  from  the 
left  side  of  the  head,  neck  and  upper  extremity.  A 
smaller  duct  collects  lymph  from  the  right  side  of  the 
head,  neck  and  upper  extremity  and  empties  into  the 
right  subclavian. 


CHAPTER  VII 
THE  NERVOUS  SYSTEM 

The  nervous  system  consists  of  a  large  mass,  en- 
cephalon,  lying  in  the  cranium,  the  spinal  cord,  medulla 
spinalis,  in  the  spinal  canal  and  three' sets  of  nerve  fibers 
conveying  impulse  to  and  from  these  centers,  cranial, 
spinal  and  sympathetic  nerves. 

The  central  mass  is  enveloped  in  three  membranes. 
dura  mater  (hard  mother),  pia  mater  (delicate  mother) 
and  arachnoid. 

THE  DURA  MATER 

The  dura  mater  is  a  dense  membrane  lining  the  in- 
terior of  the  skull  and  spinal  canal.  Its  outer  surface, 
in  the  skull,  corresponds  to  periosteum  while  its  inner, 
in  both  situations,  is  lined  by  endothelium.  The  cranial 
dura  gives  off  septa  which  separate  or  support  subdi- 
visions of  the  brain  and  lodge  some  of  the  venous 
sinuses. 

The  falx  major  is  attached  in  front  to  the  junction 
of  the  frontal  and  ethmoid  bones,  along  the  middle  of 
the  frontal,  junction  of  the  parietals  and  the  upper 
half  of  the  occipital  to  its  anterior  protuberance,  where 
it  joins  the  tentorium.  In  its  upper,  or  attached, 
border  is  lodged  the  superior  longitudinal  sinus.  Its 
lower  border,  which  dips  between  the  hemispheres  of  the 
brain,  lodges  the  inferior  longitudinal  sinus. 

The  tentorium  cerebelli  is   attached  posteriorly  to 

140 


THE   NERVOUS   SYSTEM  141 

the  lateral  limbs  of  the  occipital  cross,  anteriorly  to  the 
upper  border  of  each  petrous  bone,  leaving  a  large 
opening  opposite  the  basilar  process  for  the  passage  of 
the  midbrain.  Along  the  middle  of  its  upper  surface 
the  falx  major  is  attached  and  forms  the  straight 
sinus,  which  receives  blood  from  the  interior  of  the 
brain.  The  lateral  sinuses  are  formed  in  the  posterior 
attachment  of  the  tentorium.  The  upper  surface  of 
the  process  supports  the  occipital  lobe  of  the  brain 
while  the  lower  covers  the  cerebellum. 


THE  PIA  MATER 

The  pia  mater  is  a  thin  delicate  membrane  binding 
together  a  network  of  blood  vessels.  It  covers  the  en- 
tire brain  and  spinal  cord,  dips  into  the  fissures  found 
in  both  and  enters  the  cavity  in  the  interior  of  the 
cerebrum.  It  conducts  blood  vessels  to  and  from  the 
nerve  tissues. 

THE  ARACHNOID 

The  arachnoid  is  a  very  delicate  layer  investing  the 
pia  and  not  separable  from  it  in  many  places.  It  does 
not  dip  into  the  fissures  but  leaps  from  one  elevation 
to  another,  leaving,  opposite  the  depressions,  small 
spaces  between  itself  and  the  pia  called  subarachnoid 
spaces. 

THE  BRAIN 

The  brain  may  be  divided  into  cerebrum,  cerebellum, 
pons  Varolii  and  medulla  oblongata,  or  forebrain  (pro- 
sencephalon),  midbrain  (mesencephalon)  and  hindbrain 


142  ANATOMY    FOR    NURSES 

(rhombencephalon).  The  forebrain  consists  of  the  cere- 
brum with  is  commissures ;  the  midbrain  comprises  the 
aqueduct  of  Sylvius,  corpora  quadrigemina  and  crura 
cerebri  while  the  hindbrain  embraces  the  medulla,  with 
the  fourth  ventricle,  pons,  and  cerebellum. 

The  cerebrum  is  much  the  larger  part  of  the  brain. 
It  is  composed  of  gray  matter  externally,  which  is  the 
active  part  of  the  organ,  and  mainly  of  white  matter 
internally,  the  conducting  part,  though  there  are  masses 
of  gray  matter  embedded  in  the  white.  The  longitudi- 
nal fissure  divides  this  mass  into  a  right  and  left  hemis- 
phere, the  left,  in  the  right-handed,  being  the  more  ac- 
tive. The  white  matter  consists  of  fibers  connecting  dif- 
ferent parts  of  the  same  hemisphere — association  fibers; 
those  running  transversely  and  connecting  the  two 
hemispheres — cornmissural  fibers ;  and  of  many  fibers,  as 
the  corona  radiata,  which  descend  through  the  crura, 
pons,  and  medulla  to  connect  the  cerebrum  with  va- 
rious parts  of  the  body. 

The  exterior  of  each  hemisphere  is  made  up  of  alter- 
nate elevations,  convolutions  and  depressions,  fissures  or 
sulci.  Some  of  the  latter  occur  at  an  early  stage  of  fetal 
development,  or  in  brains  of  a  low  order,  and  divide  the 
hemisphere  into  lobes  which  approximately  correspond 
to  some  of  the  cranial  bones. 

The  fissure  of  Rolando,  or  central  sulcus,  runs  from 
near  the  middle  of  the  hemisphere  downward  and  for- 
ward for  two-thirds  of  its  vertical  measurement  and 
cuts  off  the  frontal  lobe  from  the  parietal. 

The  fissure  of  Sylvius,  projecting  in  front  of  the  cen- 
tral, and  partly  on  the  base  of  the  brain,  runs  upward 
and  backward  and  separates  the  back  of  the  frontal 


THE   NERVOUS   SYSTEM 


143 


144  ANATOMY   FOR   NURSES 

and  nearly  all  of  the  parietal  lobes  from  the  temporo- 
sphenoidal. 

The  parieto-occipital  fissure  is  almost  entirely  on  the 
mesial  surface  at  about  its  posterior  fifth  and  separates 
the  parietal  from  the  occipital  lobe. 

The  precentral  and  postcentral  sulci  run  in  front  of, 
and  behind,  the  central  and  cut  off  the  ascending  frontal 
and  parietal  convolutions.  This  area  is  one  of  the  best 
known  areas  in  the  brain.  The  frontal  furnishes  the  great 
motor  and  the  parietal  the  great  sensory  area  of  the 
brain.  The  remainder  of  the  frontal  lobe  is  probably,  the 
area  for  thought.  The  occipital,  on  its  inner  surface,  is 
marked  by  a  wedge-shaped  area,  the  cuneus,  which  is  con- 
cerned in  vision.  Hearing  is  governed  by  the  temporo- 
sphenoid  lobe  just  below  the  Sylvian  fissure.  Taste  is  in 
the  anterior  part  of  the  same  lobe  and  smell  is  in  a 
set  of  fibers  connected  with  this  lobe  but  not  forming  an 
integral  part  of  it. 

The  fibers  at  the  bottom  of  the  longitudinal  fissure  are 
called  the  corpus  callosum,  and  bind  the  hemispheres  to- 
gether so  that  their  action  may  be  coordinated. 

The  fibers  which  pass  in  a  general  direction  from 
above  downward,  form  the  corona  radiata  and  connect 
the  surface  of  the  brain  with  the  exterior  of  the  body 
through  the  nerves.  These  fibers  pass  between  two 
masses  of  gray  matter  embedded  in  the  brain  and  form 
the  internal  capsule.  This  brings  together  the  motor  and 
sensory  fibers  in  a  very  narrow  space,  so  that  a  very  small 
foreign  body  can  compress  a  large  number  of  fibers  and 
do  great  damage. 

Under  the  corpus  callosum  there  is  an  irregular  cav- 
ity partly  in  each  hemisphere  and  partly  in  the  space 


THE   NERVOUS   SYSTEM 


145 


between  them,  called  the  ventricular  cavity.  This  di- 
vides into  four  compartments  known  as  the  two  lateral, 
third  and  fourth  ventricles.  The  fourth  is  on  the  pons 
and  medulla. 

The  inferior  surface  of  the  brain  corresponds  to  the 
steplike  arrangement  of  the  upper  face  of  the  base  of 
the  skull.  It  shows  the  origin  of  the  cranial  nerves 
and  the  arrangement  of  the  blood  vessels  of  the  brain. 


I  Corpus 


callosum 


— Vision 


Olfactory 
gustatory 


— Cerebellum 


Pons 
Medulla  oblongata 

Fig.    18. — Brain,   mesial   view. 


The  crura  cerebri  are  chiefly  made  of  the  fibers  of 
the  corona  radiata  which  they  are  transmitting  to  the 
spinal  cord.  They  appear,  on  the  base  of  the  brain,  as 
tAvo  round  cords,  as  large  as  a  finger,  which  converge 
as  they  pass  downward  and  backward  to  the  pons,  into 
which  they  abruptly  disappear. 


146  ANATOMY   FOR   NURSES 

The  pons  varolii  appears  to  consist  of  two  rope-like 
bundles  running  from  the  hemispheres  of  the  cerebel- 
lum and  blending  in  a  broad  mass,  grooved  longitudi- 
nally, on  the  midline.  These  superficial  fibers  are  com- 
missural  fibers  of  the  cerebellum  and  cover  the  longi- 
tudinal fibers  of  the  crura. 

The  cerebellum  juts  into  the  occipital  fossae  between 
the  occipital  lobes  of  the  cerebrum  above  and  the  me- 
dulla below.  The  fissure  separating  it  from  the  cere- 
brum is  called  the  transverse  fissure  and  lodges  the  ten- 
torium.  Between  it  and  the  medulla  there  is  a  fissure 
Avithout  name  and  with  no  process  of  the  dura.  The 
cerebellum  consists  of  two  lateral  lobes  and  a  middle 
lobe,  the  vermis,  each  having  upper  and  lower  surfaces. 
It  is  not  convoluted  like  the  cerebrum  but  split  into  thin 
layers  by  narrow  sulci  so  that  its  folds  are  piled  like 
tiles  or  shingles. 

The  medulla  oblongata  is  the  connecting  link  between 
the  brain  and  the  spinal  cord.  It  lies  just  beneath  the 
cerebellum  and  tAvo  bundles  of  its  fibers  can  be  traced 
directly  into  that  body.  They  are  known  as  direct  cere- 
Cellar  fibers  in  the  cord  and  become  the  restiform  bodies 
in  the  medulla  from  which  they  pass  to  the  cerebellum, 
forming  its  inferior  peduncles.  Between  these  diverging 
bundles  is  seen  the  lower  half  of  the  diamond-shaped 
space  called  calamus  scriptorius,  which  forms  part  of  the 
floor  of  the  fourth  ventricle  and  gives  origin  to  several 
cranial  nerves.  The  upper  half  of  the  diamond  is  on 
the  pons.  The  floor  of  the  space  is  marked  by  a  groove 
on  the  midline. 

The  front  of  the  medulla  is  also  grooved  longitudi- 
nally and  presents  a  round  eminence  on  either  side 


THE   NERVOUS   SYSTEM  147 

called  the  anterior  pyramid.  They  are  made  up  of  fibers 
going  to  or  coming  from  the  crus  of  that  side  and  de- 
scend from  the  medulla  into  the  cord.  The  larger  part 
of  these  fibers,  however,  cross  beneath  the  floor  of  the 
median  fissure  to  the  opposite  side  of  the  cord,  forming 
the  crossed  pyramidal  tract ;  and  this  crossing  explains 
the  fact  that  injury  to  the  motor  area  of  one  hemisphere 
of  the  cerebrum  causes  paralysis  of  the  opposite  side. 

THE  SPINAL  CORD 

No  line  or  fissure  marks  the  point  of  division  be- 
tween the  medulla  and  cord,  which  corresponds  to  the 
upper  two-thirds  of  the  vertebral  column.  It  is  some- 
what flattened  from  before  backward  and,  unlike  the 
brain,  has  its  gray  matter  in  the  middle.  It  is,  appar- 
ently, mainly  a  set  of  conducting  fibers  to  carry  impulses 
to  and  from  the  brain  and  transmit  them  to  the  spinal 
nerves.  It  is  marked  by  anterior  and  posterior  fissures 
and,  on  either  lateral  half,  by  two  sets  of  openings 
marking  the  points  at  which  nerves  emerged  from  the 
cord.  Its  anterior  part  is  mainly  concerned  in  trans- 
mitting motor  impulses.  If  the  cord  be  cut  across,  the 
gray  matter  in  the  center  is  seen  to  be  arranged  some- 
what like  a  capital  H,  whose  large  end  is  in  front  and 
whose  posterior  horns  are  longer,  as  well  as  smaller, 
than  the  anterior.  The  anterior  give  attachment  to 
motor  and  the  posterior  to  sensory  nerve  fibers. 

BLOOD  VESSELS  OF  THE  BRAIN 

Blood  is  carried  to  the  brain  by  branches  of  the  in- 
ternal carotid  and  vertebral  arteries.  From  the  carotid 


148  ANATOMY  FOR  NURSES 

the  anterior  cerebral  runs  in  the  longitudinal  fissure  and 
supplies  the  mesial  face  of  the  hemisphere.  The  middle 
cerebral  lies  in  the  fissure  of  Sylvius  and  is  the  chief 
supply  to  the  cortex  of  the  frontal,  parietal,  and  temporo- 
sphenoidal  lobes.  The  anterior  choroid  enters  the  apex 
of  that  lobe  and  supplies  the  choroid  plexus  in  the  ven- 
tricular cavity. 

The  two  vertebral  arteries  unite  to  form  the  basilar 
which  runs  to  the  upper  border  of  the  pons  and  divides 
into  two  posterior  cerebral  arteries  which  pass  to  the  pos- 
terior lobe  of  the  cerebrum.  Before  the  formation  of  the 
basilar,  the  vertebral  supplies  the  spinal  cord  and  its 
membranes  and  an  inferior  cerebellar  to  the  cerebellum. 
The  basilar  gives  anterior  and  superior  cerebellar 
arteries. 

THE  CIRCLE  OF  WILLIS 

The  two  anterior  cerebral  arteries  are  united  by  a 
short  branch,  the  anterior  communicating.  The  posterior 
communicating  is  a  branch  of  the  internal  carotid  which 
joins  the  posterior  cerebral.  These  anastomoses  form 
an  irregular  circle  at  the  base  of  the  brain.  Blood 
starting  at  the  right  internal  carotid  could  pass  througli 
the  anterior  cerebral,  anterior  communicating,  left  an- 
terior cerebral,  left  carotid,  posterior  communicating 
and  posterior  cerebral  into  the  basilar  and  thence  for- 
ward through  the  right  posterior  cerebral  and  posterior 
communicating  into  the  right  carotid. 

From  the  circle  of  Willis  branches  called  ganglionic 
arise  which  pierce  the  base  of  the  brain  and  are  dis- 
tributed to  its  deep  substance.  These  arteries  are  called 
terminal  because  they  do  not  anastomose  in  the  cerebral 


THE   NERVOUS   SYSTEM  149 

substance  and,  if  one  of  them  be  destroyed  or  occluded, 
the  area  which  it  supplies  dies  from  lack  of  blood;  i.  e., 
there  is  no  collateral  circulation,  as  on  the  surface  of 
the  brain  or  elsewhere  in  the  body. 

The  return  circulation  is  cared  for  by  cerebral  veins 
formed  on  the  surface  and  in  the  interior.  The  super- 
ficial empty  into  the  longitudinal  and  cavernous  sinuses 
while  the  deep  unite  to  form  the  veins  of  Galen  which 
empty  into  the  straight  sinus. 

THE  NERVES 

The  nerves  are  twelve  pairs  of  cranial  and  thirty-one 
pairs  of  spinal  nerves  in  addition  to  the  sympathetic. 

The  Cranial  Nerves 

The  cranial  nerves  are  known  by  number  from  before 
backward  and  have  also  names  more  or  less  derived 
from  their  function.  Four  are  appropriated  to  the 
special  senses  of  smell,  sight,  hearing  and  taste.  Three 
are  concerned  in  the  movements  of  the  eye,  one  in  sup- 
plying sensation  to  the  face  and  motion  to  the  lower 
jaw;  one  in  supplying  motion  to  the  facial  muscles,  one 
to  those  of  the  tongue,  one  is  almost  a  spinal  nerve  and 
is  distributed  in  the  neck,  while  the  tenth  scatters 
fibers  from  the  head  to  the  abdomen. 

Nerve  fibers  conduct  impulses  to  the  brain  or  carry 
orders  from  the  brain.  Sensory  nerves,  like  those  re- 
cognizing pain,  all  convey  impulses  from  the  periphery 
to  the  center,  while  nerves  which  give  rise  to  motion, 
secretion,  etc.,  carry  impulses  from  center  to  periphery. 

The  olfactory,  or  first,  nerve  recognizes  odors  and 


150  ANATOMY    FOR    NURSES 

conveys  that  sensation  to  the  brain,  and  no  other.  It 
can  be  seen  at  the  base  of  the  brain  on  either  side  of 
the  longitudinal  fissure  in  the  form  of  an  elongated  mass 
of  brain  tissue  which  sends  numerous  filaments  through 
the  cribriform  plate  of  the  ethmoid  to  the  nose. 

The  optic,  or  second,  nerve  springs  from  the  optic 
chiasum  formed  at  the  junction  of  the  anterior  and  mid- 
dle cranial  fossae  by  the  union  of  two  flat  bands,  the 
optic  tracts,  which  run  over  the  crura  cerebri  to  pass 
into  the  midbrain  and  be  connected  with  the  cuneus. 
The  middle  fibers  in  these  tracts  decussate,  i.  e.,  fibers 
from  the  right  hemisphere  pass  into  the  left  eye;  the 
outer  pass  forward  in  the  nerve  of  the  same  side ;  others, 
the  most  posterior,  run  in  the  tracts  entirely  and  are 
commissural  fibers  between  the  centers,  while  the  most 
anterior  run  from  retina  to  retina. 

The  whole  nerve  passes  through  the  optic  foramen, 
enters  the  back  of  the  eyeball  and  spreads  out  in  the 
retina. 

The  motor  oculi,  or  third,  patheticus,  or  fourth,  and 
abducens,  or  sixth,  are  all  distributed  to  muscles  of  the 
orbit,  the  fourth  entering  the  superior  oblique,  the 
sixth  the  external  rectus,  while  the  third  supplies  the 
remaining  muscles  of  the  eyeball  and  gives  the  motor 
filament  to  the  ciliary  ganglion  which  supplies  the  in- 
trinsic muscles  of  the  eye.  These  nerves  all  lie  in  the 
outer  wall  of  the  cavernous  sinus  and  enter  the  orbit 
through  the  anterior  lacerated  foramen.  Their  deep 
origin  is  from  the  floor  of  the  aqueduct  of  Sylvius  or  the 
fourth  ventricle. 

The  trifacial,  or  fifth,  nerve  has,  like  a  spinal  nerve, 
two  roots  of  which  the  smaller  is  motor.  It  furnishes 


THE    NERVOUS    SYSTEM  151 

sensation  to  all  the  teeth,  the  face,  front  and  sides  of 
the  head  to  the  vertex,  and  motion  to  the  muscles  of 
mastication. 

It  can  be  seen  emerging  from  the  side  of  the  pons 
while  its  nucleus  of  origin  is  in  the  floor  of  the  fourth 
ventricle.  An  enlargement,  the  ganglion  of  Gasser,  is 
formed  on  the  posterior  root  while  lying  on  the  petrous 
bone.  The  nerve  now  splits  into  three  branches,  ophthal- 
mic, superior  maxillary  and  inferior  maxillary. 

The  ophthalmic  division  passes  through  the  sphenoidal 
fissure  and  breaks  up  into  a  lachrymal  branch  to  the 
gland  of  that  name  and  the  outer  angle  of  the  orbit;  a 
frontal  which,  dividing  into  siipraorbital  and  supra- 
trochlear,  named  from  their  points  of  exit  from  the  orbit, 
supply  muscles  and  integument  of  the  forehead  and  the 
upper  eyelid ;  and  nasal  which  crosses  the  orbit,  reenters 
the  cranium  and  descends  the  nose  in  a  groove  on  the 
nasal  bone  to  become  superficial  at  the  lower  end  of 
that  bone  and  be  distributed  to  its  tip.  It  supplies  the 
sensory  twig  to  the  ciliary  ganglion. 

The  superior  maxillary  division  leaves  the  skull 
through  the  foramen  rotundum  and  supplies  the  teeth  of 
the  upper  jaw,  the  skin  over  the  cheek  bone,  sensory 
fibers  to  Meckel's  ganglion  and,  by  an  infraorbital  nerve, 
palpebral,  nasal  and  labial  branches  to  the  lower  lid, 
nose,  and  upper  lip. 

The  inferior  maxillary  division  carries  all  the  motor 
fibers.  The  entire  nerve  leaves  the  skull  through  the 
foramen  ovale  and,  at  the  base  of  the  skull  breaks  up 
into  an  anterior  trunk,  which  contains  the  motor  fibers 
for  the  temporal,  masseter  and  pterygoid  muscles,  and  a 
sensory  twig  to  the  buccinator,  and  a  posterior  trunk 


152  ANATOMY   FOR    NURSES 

which  splits  into  inferior  dental,  gustatory  and  auriculo- 
temporal. 

The  inferior  dental  enters  the  foramen  in  the  ramus 
of  the  lower  jaw,  runs  in  the  tunnel  under  the  teeth, 
supplying  a  branch  to  every  fang  of  every  tooth,  and,  di- 
viding near  the  mental  foramen,  sends  one  branch  for- 
ward in  the  bone  to  supply  the  incisor  teeth,  while  the 
larger  division  escapes  through  the  mental  foramen  to 
give  sensation  to  the  lower  lip.  It  gives  off  a  large 
branch,  before  entering  the  dental  foramen,  to  supply 
the  mylo-hyoid  and  posterior  belly  of  the  digastric. 

The  gustatory  or  lingual  nerve  runs  down  parallel  with 
the  lower  jaw  to  the  anterior  part  of  the  tongue  where  it 
splits  into  many  branches  for  the  numerous  papillae  of 
that  organ.  It  carries  with  it  the  chorda  tympani  branch 
of  the  seventh  whose  fibers  are  mainly  distributed  to 
the  tongue,  but  many  pass  through  the  submaxillary 
ganglion  to  the  submaxillary  and  sublingual  glands. 

The  auriculo-temporal  passes  up  over  the  zygoma,  just 
in  front  of  the  ear  to  the  skin  of  the  temporal  region. 

The  facial  or  seventh  nerve  also  has  two  roots.  It 
springs  from  the  side  of  the  medulla,  between  the  resti- 
form  and  olivary  bodies  as  do  the  eighth,  ninth,  tenth, 
and  eleventh,  pursues  a  tortuous  course  through  the 
petrous  bone,  emerges  through  the  stylo-mastoid  fora- 
men, crosses  the  carotid  artery  on  a  level  with  the  lobe 
of  the  ear  and  breaks  up  into  a  whip-lash  of  branches 
which  supply  all  the  muscles  of  expression.  In  addi- 
tion it  furnishes  motor  fibers  to  the  stapedius,  stylo- 
hyoid  and  posterior  belly  of  the  digastric  and,  by  its 
cervical  branch  to  the  platysma. 

The  chorda  tympani  branch  joins  the  gustatory  ancj 


THE    NERVOUS    SYSTEM  153 

is  the  nerve  of  taste  for  the  anterior  two-thirds  of  the 
tongue. 

The  facial  also  gives  a  branch  to  join  Mack  el's 
(the  sphenopalatine)  ganglion  through  the  superficial 
petrosal. 

The  auditory,  or  eighth,  nerve  emerges  from  the  side 
of  the  medulla  just  below  the  seventh.  While  it  seems 
but  one  nerve,  it  really  consists  of  two  distinct  parts,  a 
vestibular,  concerned  with  equilibrium,  which  has  its 
origin  in  the  superior  vermis  of  the  cerebellum  and  its 
distribution  in  the  vestibule  of  the  ear;  and  a  cochlear 
division,  the  nerve  of  hearing,  connected  with  the  cere- 
brum and  distributed  to  the  cochlea  of  the  internal  ear. 

The  glosso-pharyngeal,  or  ninth,  cranial  nerve  rises 
from  the  medulla  just  below  the  eighth.  Its  deep  origin 
is  in  the  floor  of  the  fourth  ventricle.  The  nerve  leaves 
the  skull  through  the  jugular  foramen,  accompanies  the 
internal  carotid  artery  and  jugular  vein  to  the  stylo- 
pharyngeus  muscle  when  it  turns  in  across  the  artery 
to  the  side  of  the  tongue,  to  the  posterior  third  of  which 
it  conveys  taste. 

It  gives  off  branches  to  the  ear  (tympanic),  pharynx 
and  tonsils. 

The  pneumogastric,  or  tenth,  or  vagus,  is  both  motor 
and  sensory.  It  rises  from  the  side  of  the  medulla  just 
below  the  ninth,  goes  through  the  jugular  foramen,  lies 
in  the  carotid  sheath  between  artery  and  vein,  passes  to 
the  neck  and,  on  the  right  side,  crosses  the  front  of  the 
subclavian  artery,  runs  to  the  back  of  the  root  of  the 
lung  where  it  spreads  out  into  a  plexus,  forms  two  cords 
to  run  down  on  the  back  of  the  esophagus  to  the  back 


154  ANATOMY   FOR    NURSES 

of  the  stomach,  where  many  fibers  are  distributed,  and 
finally  join  the  celiac  plexus. 

The  left  nerve  enters  the  thorax  between  the  carotid 
and  subclavian  arteries,  behind  the  innominate  vein, 
crosses  the  front  of  the  transverse  aorta,  forms  the  pos- 
terior pulmonary  plexus  on  the  root  of  the  left  lung, 
passes  to  the  front  of  the  esophagus,  where  it  forms  a 
plexus  with  the  right,  and  is  distributed  to  the  front 
of  the  stomach. 

The  nerve  gives  motion  and  sensation  to  the  pharynx, 
esophagus  and  stomach,  larynx,  trachea  and  bronchial 
tubes,  sensation  to  part  of  the  external  ear  and  carries 
inhibitory  and  depressor  fibers  to  the  heart. 

The  pliaryngeal  branch  joins  a  similar  branch  of  the 
ninth  and  the  sympathetic  to  form  the  pharyngeal  plexus. 

The  laryngeal  branches  are  superior  and  inferior,  the 
first  sensory  and  the  latter  motor. 

The  superior  laryngeal  is  mainly  distributed  to  the  mu- 
cous membrane  of  the  larynx,  but  also  supplies  the  crico- 
thyroid  muscle. 

The  inferior,  or  recurrent,  laryngeal  rises  on  the  right 
on  the  subclavian  and  on  the  left  011  the  transverse 
aorta.  In  each  case  it  curves  around  the  corresponding 
vessel,  runs  to  the  interval  between  trachea  and  esopha- 
gus and  enters  the  larynx  at  its  lower  back  part  to 
supply  the  intrinsic  muscles,  except  the  crico-thyroid. 

The  cardiac  branches  arise  high  and  low  in  the 
neck  and  from  the  recurrent  laryngeal.  They  join  the 
cardiac  plexuses  and  are  distributed  from  them. 

Bronchial  branches,  anterior  and  posterior,  follow  the 
bronchial  tubes  into  the  lungs. 


THE    NERVOUS    SYSTEM  155 

Esophageal  and  gastric  branches  run  to  esophagus  and 
stomach,  respectively. 

The  cardiac  branches  join  the  celiac  or  solar  plexus  on 
the  side  of  the  celiac  axis.  Branches  of  this  plexus  fol- 
low all  the  arteries  given  oft'  from  the  axis  and  hence 
the  abdominal  viscera  receive  branches  of  the  tenth 
nerve. 

The  accessory,  or  eleventh,  nerve  is  made  up  of  a 
small  cranial  portion  which  appears  just  below  the 
tenth  at  the  side  of  the  medulla,  leaves  the  skull  through 
the  jugular  foramen  and  joins  the  vagus  to  which  it 
contributes  the  fibers  which  are  distributed  by  the 
pharyngeal  and  superior  laryngeal. 

The  spinal  portion  arises  from  the  spinal  cord  as  low 
as  the  fifth  cervical,  enters  the  skull  through  the  fora- 
men magnum,  joins  the  cranial  portion  and  leaves 
through  the  jugular  foramen.  It  crosses  the  jugular 
vein,  usually  in  front,  pierces  the  sterno-mastoid  high 
up  to  enter  the  trapezius  and  is  distributed  to  those 
muscles. 

The  hypo-glossal,  or  twelfth,  springs  from  the  side  of 
the  medulla  between  the  olivary  body  and  the  pyra- 
mid. It  leaves  the  cranium  through  the  hypoglossal 
(anterior  condyloid)  foramen,  internal  to,  and  behind 
the  jugular  vein  and  internal  carotid  artery.  It  passes 
behind  these  structures  and  runs  down  to  a  point  nearly 
opposite  the  angle  of  the  jaw  external  to  the  artery. 
It  now  crosses  the  internal  carotid,  occipital  and  ex- 
ternal carotid  arteries,  rests  on  the  hypoglossus  muscle 
and  runs  into  the  tongue  to  whose  intrinsic  muscles  it 
is  distributed.  It  gives  additional  branches  to  the 
stylo-,  hyo-  and  genio-glossus  and  genio-hyoid  muscles. 


156  ANATOMY   FOR    NURSES 

As  the  nerve  crosses  the  carotids  it  gives  a  large  de- 
scending branch  which  joins  branches  from  the  second 
and  third  cervical  nerves  and  supplies  the  depressors  of 
the  hyoid,  except  the  thyro-hyoid  which  gets  its  supply 
directly  from  the  twelfth. 

Many  of  the  cranial  nerves  communicate  with  each 
other,  the  sympathetic  nerves  and  the  spinal  nerves,  but 
do  not  form  the  intimate  associations,  called  plexus, 
which  characterize  the  spinal  nerves. 

The  Spinal  Nerves 

These  nerves  form  thirty-one  pairs  which  have  their 
origin  in  the  spinal  cord  by  two  roots,  emerge  through 
the  intervertebral  foramina  and  are  distributed  to  the 
various  parts  of  the  body.  There  are  eight  spinal 
nerves  in  the  cervical,  twelve  in"  the  thoracic,  five  in 
the  lumbar  and  six  in  the  pelvic  region. 

Each  spinal  nerve  springs  by  an  anterior,  motor,  and 
a  posterior  sensory  root.  The  posterior  roots  have 
ganglia  formed  on  them  in  the  intervertebral  foramina. 
After  the  union  of  the  roots  the  nerves  split  into  an- 
terior and  posterior  divisions,  but  these  are  now  mixed 
nerves  conveying  both  motor  and  sensory  fibers,  effer- 
ent and  afferent,  from  and  to  the  brain. 

The  posterior  divisions,  generally  smaller  than  the  an- 
terior, pass  to  the  muscles  and  integument  of  the  back 
as  individual  nerves,  not  uniting  to  form  plexus  as  do 
the  anterior  roots. 

The  anterior  divisions  of  the  cervical  nerves  form  two 
intercommunications  called  the  cervical  and  ~brac}iial 
plexuses.  The  cervical  is  formed  by  the  four  upper 
cervical  nerves  and  is  distributed  to  the  muscles  and 


THE   NERVOUS   SYSTEM  157 

skin  of  the  neck  and  head.  The  brachial  supplies  the 
upper  extremity. 

The  thoracic  nerves  do  not  form  plexuses,  but  pass  out 
between  the  ribs,  along  with  the  intercostal  arteries,  to 
be  distributed  to  muscles  and  integument  in  their  course, 
the  skin  supply  being  carried  by  lateral  cutaneous 
branches  which  rise  about  midway  between  the  sternum 
and  spine.  The  lateral  cutaneous  branch  of  the  second 
intercostal  joins  a  branch  of  the  brachial  plexus  and  is 
distributed  to  the  upper  extremity.  The  lower  six  in- 
tercostal nerves  are  often  called  thoracico-abdominal 
because  they  supply  structures  on  both  the  thorax  and 
abdomen. 

The  lumbar  nerves  are  distributed,  the  upper  three 
and  a  half,  by  the  lumbar  plexus.  The  remaining  nerves 
join  the  upper  sacral  nerves  and  form  the  sacral 
plexus. 

The  spinal  nerves  carry  fibers  intended  for  the  sym- 
pathetic system  and  these  are  also  both  afferent  and 
efferent.  They  are  described  separately. 

The  Cervical  Plexus 

The  cervical  plexus  is  formed  by  intercommunication 
between  the  anterior  divisions  of  the  four  upper  cer- 
vical nerves.  This  is  a  very  loose  communication  be- 
tween the  nerves  whose  branches  are  divided  into  super- 
ficial and  deep. 

The  superficial  branches  are  all  cutaneous,  that  is,  they 
convey  common  sensations  like  pain  from  the  skin,  and 
consist  of  an  upper  and  a  lower  set.  The  upper  branches 
have  received  names  indicative  of  their  distribution, 
small  occipital  (occipitalis  minor),  great  auricular  (au- 


158  ANATOMY   FOR   NURSES 

ricularis  magnus)  and  transverse  or  superficial  cervical 
(superficialis  colli).  Together  these  nerves  supply  the 
broad  expanse  of  skin  from  that  covering  the  occiput 
to  the  sternum,  omitting  the  face,  the  occipital  taking 
that  region;  the  auricular,  the  scalp  back  of  the  ear 
and  over  the  temporal  region ;  and  the  cervical,  the  skin 
between  the  jaw  and  sternum  in  front  of  the  sterno- 
mastoid  muscle,  around  whose  posterior  border  all  these 
nerves  wind. 

The  descending  superficial  branches  emerge  from  be- 
neath the  same  muscle  and  are  divided  into  three  sets 
according  to  their  distribution,  sternal,  clavicular  and 
acromial. 

The  deep  branches  are  muscular  and  communicating. 
The  most  important  of  the  latter,  from  the  second  and 
third  nerves,  joins  the  descending  branch  of  the  tAvelfth 
cranial  for  distribution  to  the  infrahyoid  muscles. 

The  muscular  branches  aid  the  eleventh  in  supplying 
the  sternomastoid  and  trapezius.  The  plexus  also  sup- 
plies deep  muscles  of  the  neck. 

The  phrenic,  though  a  muscular  branch,  is  important. 
It  is  the  motor  nerve  of  the  diaphragm  and  hence  the 
great  inspiratory  nerve.  It  is  the  product  of  the  third 
and  fourth  nerves  of  the  plexus  and  of  the  fifth  from 
the  brachial.  Its  course  is  not  the  same  on  the  two 
sides.  On  the  right  it  crosses  the  subclavian  artery  in 
front  and  behind  the  vein,  runs  outside  the  innominate 
vein  and  superior  vena  cava,  in  front  of  the  root  of  the 
right  lung,  and  descends  on  the  pericardium  to  the 
diaphragm.  The  left  nerve  crosses  the  subclavian,  lies 
external  fo,  and  in  front  of,  the  thoracic  part  of  that 
vessel,  crosses  the  transverse  aorta  and  runs  down  the 


THE   NERVOUS   SYSTEM  159 

pericardium  to  the  diaphragm.  Both  nerves  pierce  the 
diaphragm  and  are  distributed  to  it  from  its  under  sur- 
face. 

The  Brachial  Plexus 

The  plexus  is  formed  by  the  four  lower  cervical  and 
greater  part  of  the  first  dorsal.  This  is  a  much  more 
intimate  communication  than  the  cervical.  The  plexus 
lies  between  the  scalene  muscles,  runs  downward  and 
outward  to  the  space  between  the  clavicle,  first  rib  and 
scapula,  is  in  close  relationship  to  the  second  and  third 
parts  of  the  subclavian  and  first  and  second  parts  of  the 
axillary  artery,  on  the  third  part  of  which  it  breaks  up 
into  seven  terminal  branches.  It  is  superficial  just 
above  the  clavicle  where  only  the  skin,  superficial  fas- 
cia, platysma  and  deep  fascia  cover  it.  It  is  partly  be- 
hind the  second  part  of  the  subclavian,  external  to, 
and  behind,  the  third  part  of  that  artery  and  the  first 
part  of  the  axillary  and  on  three  sides,  inner,  outer  and 
posterior,  of  the  second  part  of  the  axillary. 

The  formation  of  the  plexus  varies,  but  one  of  the 
most  frequent  modes  is  that  the  fifth  and  sixth  nerves 
unite,  the  seventh  passes  out  alone ;  the  eighth  and  first 
dorsal  form  a  cord.  The  seventh  now  joins  the  cord 
formed  by  the  fifth  and  sixth,  which  gives  off  a  large 
branch  to  unite  with  a  similar  branch  from  the  lower 
cord  and  these  form  the  posterior  cord  of  the  plexus. 
These  cords  do  not  assume  their  correct  position  until 
they  reach  the  second  part  of  the  axillary  artery,  where 
they  are  inner,  outer,  and  posterior  cords. 

Branches. — These  are  divided  first  into  wayside  and  terminal, 
and  the  former  into  those  above  and  below  the  clavicle.  Above 
the  clavicle  branches  are  given  to  the  supra-  and  infra-spinait, 


160  ANATOMY   FOR   NURSES 

rhomboid,  serratus,  magnus,  subclavius,  scalene  and  long  cervi- 
cal muscles.  Below  the  clavicle  the  branches  which  supply 
the  pectoral  and  subscapular  muscles  arise. 

The  terminal  branches  supply  all  the  remaining  structures  of 
the  upper  extremity. 

The  outer  and  inner  cords  contain  fibers  from  all  the  nerves 
of  the  plexus.  Each  gives  a  bra.nch  to  form  the  median  nerve 
on  the  front  of  the  third  part  of  the  axillary. 

The  Median  Nerve 

The  median  nerve  passes  to  the  middle  of  the  front 
of  the  elbow  without  giving  off  branches,  accompany- 
ing the  axillary  and  brachial  arteries.  It  supplies,  di- 
rectly or  through  its  interosseous  branch,  all  the  mus- 
cles of  the  front  of  the  forearm  except  the  flexor  carpi 
ulnaris  and  the  inner  half  of  the  profundus  digitorum. 

The  nerve  then  enters  the  palm  and  supplies  the  su- 
perficial muscles  of  the  thenar  eminence  and  digital 
branches  to  the  front  of  the  fingers  except  the  little 
finger  and  inner  half  of  the  ring  finger,  and  a  branch 
to  the  skin  of  the  palm. 

The  Musculo-Cutaneous 

The  remainder  of  the  outer  cord  forms  the  musculo- 
cutaneous  nerve  which  supplies  the  muscles  of  the  an- 
terior region  of  the  arm,  gives  a  branch  to  the  elbow 
and,  becoming  cutaneous,  furnishes  sensation  to  the 
skin  of  the  outer  half  of  the  forearm,  front  and  back. 

The  inner  cord  carries  fibers  of  the  eighth  cervical 
and  first  dorsal.  In  addition  to  giving  the  inner  head  of 
the  median,  it  splits  into  three  branches,  lesser  internal 
cutaneous,  internal  cutaneous  and  ulnar. 


THE   NERVOUS   SYSTEM  161 

The  Lesser  Internal  Cutaneous 

^/St-^MHt       «3>TxCki0u 

The  lesser  internal  cutaneous  receives  the  lateral 
cutaneous  branch  of  the  second  intercostal,  which  some- 
times nearly  replaces  it,  and  is  distributed  to  the  skin 
covering  the  lower  third  of  the  postero-internal  aspect 
of  the  arm. 

The  Internal  Cutaneous 

^V^A.,0.1         0(^1^      &\*-Q.bi(^( 

The  in  tern  a.  I  cutaneous  takes  up  the  supply  of  the 
skin  of  the  forearm  where  the  musculo-cutaneous  ceases. 
It  supplies  about  one-half  of  the  forearm,  commencing 
at  the  middle  of  the  front  and  continuing,  by  the  inner 
side,  to  the  middle  of  the  back. 

The  Ulnar 

The  ulnar  nerve  is  the  continuation  of  the  inner  cord. 
It  is  a  musculo-cutaneous  nerve,  supplying  the  inner 
part  of  the  elbow  joint,  the  flexor  carpi  ulnaris  and  inner 
half  of  the  flexor  profundus  digitorum  in  the  forearm, 
all  the  muscles  of  the  hypothenar  group  and  the  deep 
muscles  of  the  thenar  in  the  hand.  By  a  dorsal  branch 
it  supplies  about  half  the  back  of  the  hand  and  the 
palmar  aspect  of  half  the  ring  and  all  of  the  little 
fingers.  The  nerve  passes  down  the  arm  diverging 
from  the  brachial  artery,  forms  the  " funny  bone"  by 
lying  between  the  internal  condyle  and  olecranon  and 
lies  to  the  inner  side  of  the  ulnar  artery  in  the  lower 
two-thirds  of  its  course. 

The  posterior  cord  has  fibers  from  all  the  nerves. 
It  is  a  large  cord  behind  the  third  part  of  the  axillary 
which  is  distributed  to  the  neighborhood  of  the  shoul- 


162  ANATOMY   FOR   NURSES 

der  by  a  branch  called  circumflex  and  to  the  back  of  the 
arm  arid  forearm  by  the  musculo-spiral  or  radial. 

The  Circumflex 

The  circumflex  is  distributed  to  the  teres  minor  and 
deltoid  muscles,  the  shoulder,  and  the  skin  of  the  deltoid 
region.  It  winds  around  the  shaft  of  the  humerus  with 
the  posterior  circumflex  artery. 

The  Musculo-Spiral 

The  musculo-spiral,  or  radial,  winds  around  the  hu- 
merus in  the  musculo-spinal  groove  until  it  reaches 
the  interval  between  the  brachio-radialis  and  brachialis 
anticus  where  it  gives  off  the  posterior  interosseous  and 
continues  down  the  forearm  as  the  radial  nerve. 

In  the  arm  it  furnishes  sensation  to  the  skin  of 
the  posterior  and  outer  aspects  and  muscular  fibers  to 
the  triceps.  In  the  forearm  it  supplies,  directly,  or  by 
its  interosseous  branch,  all  .the  muscles  on  the  back 
and  outer  side  of  the  forearm. 

The  radial  continuation  is  a  nerve  of  sensation  only. 
Passing  to  the  back  of  the  forearm  at  its  lower  fourth,  it 
furnishes  branches  to  the  back  of  the  hand  on  the  radial 
side  and  the  fingers  as  far  as  the  cleft  between  the  ring 
and  middle  fingers. 

The  Lumbar  Plexus 

This  is  a  loosely  connected  plexus  behind  the  psoas 
magnus  muscle  formed  from  the  first,  second,  third,  and 
part  of  the  fourth  anterior  lumbar  divisions. 

Ilio-Hypogastric  and  Ilio-Inguinal 

The  first  branches,  called  ilio-hypogastric  and  ilio-in- 
guinal  correspond  to  intercostal  nerves,  in  that  they 


THE    NERVOUS    SYSTEM  163 

wind  around  the  body  in  the  muscular  layers  and  sup- 
ply the  muscles  and  skin  on  the  lower  part  of  the  abdo- 
men, the  ilio-inguinal  descending  to  the  skin  of  the  upper 
inner  part  of  the  thigh  and  to  the  external  genitals. 

The  Genito-Femoral 

This  is  the  nerve  to  the  cremaster  muscle  of  the  male 
or  round  ligament  of  the  female.  It  also  gives  a  branch 
which  supplies  the  skin  over  Scarpa's  triangle. 

The  Lateral  Femoral 

The  lateral  femoral,  external  cutaneous,  supplies  the 
skin  over  the  antero-external  and  external  faces  of  the 
thigh  as  far  as  the  knee. 

The  Femoral 

The  femoral,  anterior  crural,  is  the  largest  branch  of 
the  plexus  being  distributed  from  within  the  pelvis  as 
far  as  the  great  toe.  It  is  a  musculo-cutaneous  nerve. 
It  passes  under  Poupart's  ligament,  external  to  the 
psoas  magnus,  and  lies  about  a  quarter  of  an  inch  ex- 
ternal to  the  femoral  artery,  where  it  breaks  up  into 
superficial  and  deep  branches.  The  deep  branches  sup- 
ply the  anterior  femoral  muscles,  except  the  sartorius, 
while  the  superficial  under  the  names  middle  and  inter- 
nal cutaneous  and  long  saphenous  furnish  sensation  to 
the  skin  of  the  front  and  inner  sides  of  the  thigh,  inner 
side  of  the  leg,  and  inner  side  of  the  great  toe.  The  mid- 
dle cutaneous  also  supplies  the  sartorius. 

The  long  saphenous  is  the  longest  nerve  in  the  body.  It 
accompanies  the  vein  of  the  same  name  below  the  knee 
joint,  its  branches  fairly  corresponding  to  the  tribu- 
taries of  the  vein. 


164  ANATOMY   FOR   NURSES 

The  Obturator 

The  obturator  crosses  the  pelvic  Avail  above  the  ob- 
turator vessels,  leaves  the  pelvis  through  the  obtrurator 
foramen  and  breaks  up  into  many  branches  which  sup- 
ply muscles  of  the  adductor  group,  including  the  gracil- 
is,  the  hip  and  knee  joints  and  the  obturator  externus. 

The  Sacral  Plexus 

The  remainder  of  the  fourth  lumbar  unites  with  the 
fifth  to  form  the  lumbo-sacral  cord  which  passes  over 
the  pelvic  brim  to  unite  with  the  three  upper  and  half 
of  the  fourth  sacral  nerves  to  form  the  sacral  plexus. 
This  plexus  lies  on  the  front  of  the  sacrum,  separated 
from  it  by  the  pyrif ormis  muscle,  with  the  internal  iliac 
vessels  in  front  of  it  and  covered  by  the  peritoneum  and 
pelvic  viscera.  It  gives  branches  to  the  external  rota- 
tors of  the  thigh,  a  gluteal  branch  to  the  muscles  of 
that  name,  an  internal  pudic  or  pudendal  nerve  to  ac- 
company the  artery  of  the  same  name  and  be  distributed 
to  the  genital  organs  and  the  perineum,  and  terminates 
by  dividing  into  a  lesser  sciatic  nerve  to  the  skin  of  the 
back  of  the  thigh  and  the  gluteus  maximus  muscle  and  a 
great  sciatic  which  supplies  the  remainder  of  the  lower 
extremity. 

The  Great  Sciatic 

The  great  sciatic,  much  the  largest  nerve  in  the  body, 
leaves  the  pelvis,  below  the  pyriformis,  through  the 
great  sacro-sciatic  foramen  and  runs  down  the  middle 
of  the  back  of  the  thigh  to  the  popliteal  space  where  it 
divides  into  the  tibial  (internal  popliteal)  and  common 
peroneal  (external  popliteal)  nerves.  It  supplies  the 
hip  joint  and  the  posterior  femoral  muscles. 


THE    NERVOUS    SYSTEM  165 

The  tibial  nerve  accompanies  the  popliteal  artery  and 
vein  through  the  popliteal  space,  lying  superficial  to 
both,  and  then  the  posterior  tibial  artery,  to  which  it  is 
external  hxits  lower  two-thirds,  to  the  ankle  joint  be- 
tween the  os  calcis  and  internal  malleolus,  where,  like 
the  artery,  it  divides  into  internal  and  external  plantar 
nerves. 

It  supplies  three  branches  of  the  knee  joint,  muscu- 
lar branches  for  all  the  muscles  on  the  back  of  the  leg, 
a  cutaneous  branch  to  the  short  saphenous,  formed  by 
this  and  a  branch  of  the  peroneal,  which  supplies  the 
skin  of  the  back  of  the  leg  and  inner  side  of  the  foot, 
and  cutaneous  branches,  calcanean,  to  the  inner  side  of 
the  heel  and  sole. 

The  Plantar  Nerves 

The  internal  plantar,  larger  than  the  external,  gives 
motor  fibers  to  the  muscles  of  the  inner  half  of  the  foot 
and  cutaneous  branches  to  the  inner  three  and  a  half 
toes. 

The  external  plantar  gives  motor  twigs  to  the  super- 
ficial muscles  of  the  outer  side  of  the  foot,  and  to  most 
of  the  deep  muscles,  and  sensory  branches  to  the  little 
toe  and  outer  side  of  the  fourth. 

The  Common  Peroneal 

The  common  peroneal,  external  popliteal,  nerve  sup- 
plies two  twigs  to  the  knee  joint,  a  cutaneous  branch  to 
aid  in  forming  the  short  saphenous  and  divides  into  a 
deep  peroneal  (anterior  tibial)  and  a  superficial  peroneal 
(musculo-cutaneous) . 


166  ANATOMY    FOR    NURSES 

The  deep  peroneal,  or  anterior  tibial,  nerve  accompa- 
nies the  anterior  tibial  artery  on  the  interosseous  mem- 
brane, supplies  the  muscles  of  the  front  of  the  leg  and 
dorsum  of  the  foot  and  terminates  in  cutaneous  branches 
to  the  adjoining  sides  of  the  great  and  second  toes.  It 
also  supplies  the  ankle  and  tarsal  articulations. 

The  superficial  peroneal,  or  musculo-cutaneous,  de- 
scends with  the  peroneal  muscles,  which  it  supplies,  and 
is  distributed  to  the  inner  side  of  the  great  toe,  skips  the 
next  cleft  and  supplies  the  toes  from  the  outer  side  of 
the  second  to  the  inner  side  of  the  fourth  inclusive. 

The  cutaneous  nerves,  particularly  in  the  hand  and 
foot,  communicate  with  each  other,  but  by  no  means  so 
frequently  or  so  intimately  as  to  the  arteries  and 
veins. 

The  Sympathetic  Nerves 

The  sympathetic  nerves  preside  over  the  nonstriated 
muscular  fibers ;  and,  as  this  is  very  widely  distributed, 
occurring  especially  in  the  viscera  and  in  the  vascular 
system  throughout  the  body,  the  sympathetic  nerves 
have  an  equally  wide  range. 

The  essential  elements  of  the  system  are  a  series  of 
ganglia  receiving  fibers  from  cranial  or  spinal  nerves, 
giving  communications  to  each  other  and  adjacent 
nerves,  and  branches  of  distribution  to  the  viscera  and 
vessels,  which  usually  spring  from  plexuses  formed  by 
intercommunications  between  various  branches  of  dis- 
tribution. 

Three  of  these  ganglia,  the  ciliary,  spheno-palatine,  or 
Meckel  's,  and  the  otic  are  connected  with  the  divisions  of 
the  fifth  nerve  and  constitute  a  large  part  of  the  ce- 
phalic portion  of  the  sympathetic,  the  remainder  of 


THE    NERVOUS    SYSTEM  167 

which    follows    the    internal    carotid    artery    and    its 
branches. 

The  ciliary  ganglion,  supplying  the  nonstriated  muscle 
of  the  eyeball,  situated  on  the  outer  side  of  the  optic 
nerve,  is  the  most  important.  MecUel's  lies  near  the 
spheno-palatiiie  foramen  and  gives  branches  to  the 
orbit,  nose,  soft  palate  and  pharynx. 

The  Gangliated  Cord 

Though  directly  continuous  with  the  cephalic  por- 
tion, the  spinal  sympathetic  is  described  as  if  it  were 
distinct.  It  consists  of  a  series  of  ganglia  irregularly 
corresponding  to  the  spinal  nerves,  lying  in  the  neck, 
behind  the  carotid  vessels,  in  the  thorax  on  the  head  of 
the  ribs,  in  the  abdomen  along  the  inner  side  of  the 
psoas  ma  gnus  and  in  the  pelvis  on  the  front  of  the 
sacrum.  In  the  neck  there  are  three  ganglia,  though 
the  superior  gives  evidence  of  the  coalescence  of  four, 
the  middle  and  inferior  of  two  each.  In  the  thorax  the 
number  generally  corresponds  to  the  number  of  nerves, 
though  two  may  coalesce.  In  the  lumbar  region  there 
are  four  and  in  the  pelvic  four  or  five. 

Each  ganglion  consists  of  ascending  branches  which 
run  in  the  cord  to  the  ganglion  above,  descending  to  the 
one  below,  external,  wrhich  consist  of  two  sets  of  fibers, 
going  to  and  from  the  spinal  nerves,  and  internal  or 
branches  of  distribution. 

From  the  cervical  ganglia  come  the  branches  which 
supply  the  blood  vessels  of  the  region,  larynx  and 
pharynx  and  the  cardiac  branches,  which  unite  with 
branches  from  the  pneumogastric  to  form  the  great 
plexus  from  which  the  heart  is  supplied. 


168  ANATOMY   FOR    NURSES 

The  thoracic  ganglia  supply  the  aorta  and  its  branches 
and  the  lungs  by  branches  from  the  upper  five,  while  the 
lower  seven  produce  the  splanchnic  nerves  which  enter 
the  abdominal  cavity  and  are  distributed  to  its  viscera 
and  vessels  after  joining  the  celiac  or  semilunar  ganglia. 

The  celiac,  or  solar,  plexus  is  a  great  mass  of  sympa- 
thetic fibers  surrounding  the  origin  of  the  celiac  axis 
and  the  superior  mesenteric  artery.  From  it  branches 
are  derived  which  form  smaller  plexus  on  all  the  arte- 
ries in  this  region.  We  thus  have  gastric,  hepatic, 
renal,  and  mesenteric  plexus  formed  from  which  the 
ultimate  distribution  takes  place. 

The  lumbar  ganglia  give  branches  to  form  the  aortic 
plexus  and  others  which  pass  to  the  iliac  vessels  and 
form  the  hypogastric  plexus,  from  which  branches  are 
given  to  the  pelvic  viscera. 

The  pelvic  ganglia  give  branches  to  the  pelvic  plexus 
and  unite  in  the  ganglion  inpar  on  the  front  of  the 
coccyx. 


CHAPTER  VIII 
ORGANS  OF  THE  SENSES 

The  special  senses  are  taste,  smell,  sight,  and  hearing. 

TASTE 

The  organ  of  taste  is  located  in  the  papillae  on  the 
tongue,  a  muscular  organ  consisting  of  bundles  of 
muscle  fibers  running  longitudinally,  vertically  and 
horizontally  which  enable  it  to  change  its  shape  and 
position,  located  in  the  space  between  the  diverging 
prongs  of  the  lower  jaw  and  attached  by  its  base  to  the 
hyoid  bone.  From  the  anterior  two-thirds  of  the 
tongue,  taste  sensation  is  conveyed  by  the  chorda  tym- 
pani  nerve,  while  the  glosso-pharyngeal  supplies  the 
posterior  third. 

SMELL 

The  external  organ  of  smell  is  the  nose,  a  pyramidal 
projection,  base  downward,  thrust  forward  between  the 
eyes  on  either  side  above  and  the  mouth  below. 

The  nose  is  covered  by  skin  and  divided  into  two 
cavities  by  a  vertical  median  septum  whose  anterior 
third  is  cartilage  and  posterior  tAvo-thirds  bone,  made 
up  of  the  perpendicular  plate  of  the  ethmoid  and  the 
vomer.  This  constitutes  the  inner  wall  of  each  nostril, 
whose  outer  wall  is  composed  of  three  shelf-like  pro- 
jections of  bone,  the  superior,  middle,  and  inferior  trru- 

169 


170  ANATOMY   FOR    NURSES 

binates,  with  intervening  spaces  which  give  this  wall  a 
convoluted  appearance.  The  bones  and  spaces  increase 
in  length  from  above  downward.  The  roof  slopes  up 
in  front,  runs  straight  back  in  the  middle  and  down- 
ward and  backward  behind.  The  whole  is  covered  by 
mucous  membrane,  continuous  with  the  skin  in  front, 
the  lining  of  the  nasopharynx  and  eustachian  tubes 
leading  into  the  ear  behind,  the  hollow,  or  antrum,  of 
the  upper  jaw  on  the  side  and  the  eyes  above.  This 
membrane  is  particularly  thick  and  vascular  over  the 
turbinates.  The  upper  part  of  the  nostrils  is  the  olfac- 
tory area  in  which  the  filaments  of  the  first  nerve  are 
distributed.  The  lower  part  of  each  cavity  is  the 
respiratory  region. 

SIGHT 

The  opening  between  the  eyelids  is  called  the  palpe- 
bral  fissure. 

The  eyelids,  of  which  the  upper  is  the  more  movable, 
consist  of  two  plates  of  cartilage,  tarsal  plates,  covered 
by  delicate  skin  and  areola  tissue  with  some  pale  muscu- 
lar fibers  surrounding  the  fissure.  Next  the  eyeball 
they  are  lined  by  a  mucops  membrane,  the  conjunctiva, 
which  spreads  from  lid  to  eyeball  and  covers  the  tarsal 
glands  lying  between  it  and  the  cartilage.  The  two  lids 
join  internally  and  externally,  but  the  fissure  is  enlarged 
internally  and  the  margins  of  the  lids  show  each  a  minute 
opening,  puncta  lachrymalia,  the  beginning  of  the  lach- 
rymal ducts  which  unite  in  the  lachrymal  sac,  lodged  in 
the  groove  on  the  lachrymal  bone,  which  contracts  to 
form  the  naso-larchrymal  duct  conveying  the  tears  to 
the  nose. 


ORGANS   OF    THE   SENSES  171 

The  lachrymal  gland,  which  secretes  the  tears,  is  situ- 
ated in  the  hollow  at  the  outer  angle  of  the  orbit.  The 
ducts  pour  out  the  secretion  on  the  conjunctiva  whence 
it  is  carried  into  the  nose. 

The  eyelids  are  studded  with  hairs,  the  eyelashes,  and 
a  thicker  growth  of  hair  along  the  orbital  ridge  forms 
the  eyebrow. 

THE  EYE 

The  organ  of  vision  is  a  ball  formed  of  a  protecting 
coat,  sclerotic,  a  vascular  coat,  choroid  and  a  visual  coat, 
retina,  containing  three  refracting  media,  aqueous  hu- 
mor, crystalline  lens,  and  vitreous  humor. 

The  eyeball  is  not  quite  globular.  Its  posterior  five- 
sixths,  formed  by  the  sclerotic,  is  a  segment  of  a  large 
sphere  on  the  front  of  which  is  imposed  a  segment  of  a 
small  sphere,  one-sixth  of  the  whole,  formed  by  the 
cornea.  The  cornea  and  sclerotic  are  continuous,  but  the 
cornea  is  transparent  and  the  sclerotic  opaque.  A  line 
drawn  through  the  ball  from  before  backward  is  the  axis 
of  the  eye  whose  extremities  are  the  anterior  and  pos- 
terior poles.  A  line  drawn  at  right  angles  to  the  axis 
through  the  middle  and  around  the  ball  is  the  equator. 
The  optic  nerve  pierces  the  sclerotic  a  little  to  the  nasal 
side  of  its  center  and  carries  the  central  artery  of  the 
retina.  It  here  spreads  out  in  the  retina  which  has  a 
blind  spot  at  the  entrance  of  the  artery.  The  point  of 
most  acute  vision  is  a  little  external  to  this,  at  the  fovea 
centralis,  at  the  posterior  termination  of  the  axis. 

The  sclerotic  is  a  dense  fibrous  coat  pierced  behind  by 
the  optic  nerve  and,  in  front  of  that  point,  by  numerous 
openings  for  the  passage  of  vessels.  In  front  it  becomes 


172  ANATOMY   FOR    NURSES 

continuous  with  the  cornea,  corneo-scleral  junction, 
which  it  slightly  overlaps,  the  union  being  marked  by 
a  slight  groove. 

The  cornea  is  the  transparent  anterior  sixth  of  the 
outer  tunic.  It  is  convex  in  front  and  concave  behind, 
its  convexity  varying  in  different  individuals  and  at 
different  ages,  being  more  convex  in  the  young. 

The  choroid  consists  of  three  parts.  The  large  pos- 
terior portion,  enveloping  five-sixths  of  the  globe,  is 
the  vascular  tunic  of  the  eye.  This  is  succeeded  by  the 
ciliary  body,  which  continues  the  choroid  forward,  and 
is  itself  succeeded  by  the  iris,  a  curtain,  hanging  down 
behind  the  cornea,  pierced  by  a  circular  opening,  the 
pupil. 

The  ciliary  body  consists  of  a  posterior  part,  continu- 
ous with  the  choroid,  called  the  orbicularis  ciliaris;  from 
sixty  to  eighty  infoldings  of  the  choroid,  radiating  back- 
ward from  the  orbicularis,  called  ciliary  processes ;  and  a 
circular  band  3  mm.  wide  on  the  anterior  part  of  the 
choroid,  the  ciliary,  or  Bowman's  muscle.  This  consists 
of  circular  and  longitudinal  fibers.  The  latter,  the  more 
important,  may  be  described  as  rising  from  the  choroid 
and  inserting  into  the  ciliary  processes  which  are  fas- 
tened to  the  capsule  of  the  lens. 

The  iris  contains  circular  and  radiating  fibers  whose 
contractions  decrease  and  increase  the  size  of  the  pupil 
respectively.  It  hangs  in  front  of  the  lens,  not  in  con- 
tact with  it,  and  divides  the  space  between  cornea  and 
lens  and  capsule  into  anterior  and  posterior  chambers, 
the  anterior  being  limited  in  front  by  the  cornea  and 
behind  by  the  iris  and  central  part  of  the  lens,  the  pos- 
terior bounded  in  front  by  the  back  of  the  iris  and  be- 


ORGANS   OF    THE   SENSES  173 

hind  by  that  part  of  the  lens  and  capsule  beyond  the 
pupillary  opening. 

The  retina  is  the  visual  coat  of  the  eye  and  is  essen- 
tially the  spread  out  fibers  of  the  optic  nerve.  Its  ex- 
terior surface  is  in  contact  with  the  choroid  while  its 
interior  is  separated  from  the  vitreous  humor  by  the 
hyaloid  membrane.  Anteriorly  the  retina  terminates,  a 
little  behind  the  ciliary  body,  in  a  jagged  edge  called  the 
ora  serrata.  About  3  mm.  to  the  outer  side  of  the  optic 
nerve,  at  the  posterior  pole  of  the  eye,  there  is  a  yellow- 
ish oval  area,  macula  lutea  with  a  central  depression, 
fovea  centralis,  where  the  retina  is  very  thin  and  where 
vision  is  most  acute. 

The  refracting  media  are  the  aqueous  humor,  filling  the 
anterior  and  posterior  chambers,  the  lens  and  capsule 
and  the  vitreous  humor,  filling  the  posterior  and  larger 
segment  of  the  globe. 

The  aqueous  humor  is  an  alkaline  fluid  mainly  com- 
posed of  water. 

The  vitreous  humor  is  a  transparent  jelly-like  sub- 
stance, albuminous  in  character,  filling  the  hollow  of  the 
retina  from  which  it  is  separated  by  the  hyaloid  mem- 
brane. 

The  hyaloid  membrane  becomes  thickened  at  the  ciliary 
body  and  grooved  for  the  reception  of  the  ciliary  proc- 
esses. It  here  splits  into  a  very  delicate  layer  which  lies 
in  front  of  a  depression  in  the  vitreous,  the  hyaloid  fossa, 
for  the  reception  of  the  lens,  while  the  other  is  attached 
circumferentially  to  the  capsule  of  the  lens  and  forms  its 
suspensory  ligament. 

The  crystalline  lens  lies  opposite  the  ciliary  body 
between  the  iris  in  front  and  the  vitreous  behind.  It  is 


174  ANATOMY   FOR   NURSES 

circular  in  form,  transparent,  convex  on  both,  surfaces, 
though  more  so  in  front  than  behind,  and  is  enclosed  in 
structureless  transparent  membrane  called  the  capsule 
of  the  lens.  The  lens  is  an  elastic  body  which  hardens 
and  loses  its  elasticity  with  age.  It  is  kept  normally 
slightly  flattened  by  the  pull  of  the  suspensory  ligament 
on  the  capsule.  Where  it  is  required  to  accommodate 
the  eye  for  near  vision,  the  ciliary  muscle  contracts, 
draws  the  choroid  forward,  relaxes  the  suspensory  liga- 
ment and  allows  the  lens  to  expand.  When  elasticity 
is  lost  with  age,  the  muscle  may  continue  to  act,  but  the 
lens  has  lost  its  power  of  expansion. 

The  iris  reacts  to  light.  When  a  strong  light  is 
thrown  on  the  eye  the  circular  fibers  contract,  narrow 
the  pupil  and  cut  off  a  large  portion  of  the  light.  When 
the  light  becomes  dim  the  circular  fibers  relax,  the 
radiating  contract,  the  pupil  is  expanded  and  a  large 
amount  of  light  is  transmitted  through  the  lens  to  the 
retina. 

THE  EAR 

The  organ  of  hearing  consists  of  the  external,  middle 
and  internal  ear. 

The  external  ear,  auricle,  or  pinna,  is  an  irregular  car- 
tilage, covered  by  skin,  situated  at  the  side  of  the  head 
and  prolonged  into  the  canal  in  the  temporal  bone.  The 
prominent  rim  which  surrounds  the  greater  part  of  the 
circumference  is  called  the  helix;  the  depression  next  it 
the  scaphoid  fossa;  the  elevation  the  antihelix  and  the 
deep  depression  in  front  of  this  and  leading  into  the 
skull,  the  concha.  The  little  projection  overhanging  the 
auditory  canal  in  front  is  the  t rag us;  the  one  below  and 


ORGANS   OF    THE   SENSES  175 

behind  the  anti-tragus;  the  space  between  the  intertragic 
notch  and  the  end  of  the  ear  below  the  lobule. 

There  are  numerous  small  muscles  attached  to  the  ex- 
ternal ear,  but,  in  the  human  being,  they  are  nearly  al- 
ways powerless  and  it  is  a  waste  of  time  to  study 
them. 

The  external  auditory  meat  us  is  the  canal  leading  to 
the  tympanic  membrane  which  guards  the  middle  ear. 
It  is  nearly  an  inch  (2.5  cm.)  in  length,  the  outer  third 
formed  by  the  cartilage  already  examined  and  the  in- 
ner two-thirds  by  bone.  It  is  slightly  curved  with  its 
general  direction  inward,  forward  and  downward.  It 
is  closed  by  the  tympanic  membrane  set  obliquely  across 
the  canal  so  that  the  floor  and  anterior  wall  are  longer 
than  the  roof  and  posterior. 

The  middle  ear  is  a  small  slit-like  chamber  at  the  bot- 
tom of  the  auditory  canal  w^hose  essential  features  are 
an  opening  in  its  anterior  wall  by  which  air  is  conveyed 
to  the  cavity  from  the  back  of  the  nose  through  the 
auditory  or  eustachian  tube;  an  external  wall  closed  by 
the  tympanic  membrane ;  an  internal  wall  pierced  by  two 
openings  by  which  this  cavity  communicates  with  the 
inner  ear  and  a  chain  of  small  bones,  the  auditory  ossicles 
by  which  the  vibrations  of  the  tympanic  membrane  are 
conveyed  to  the  essential  organ  of  hearing  in  the  inner 
ear.  Parallel  with  the  auditory  tube  there  is  a  small 
canal  which  lodges  the  tensor  tympani  muscles,  whose 
action  is  to  stretch  the  drum  of  the  ear  (tympanic  mem- 
brane). 

The  openings  on  the  inner  wall  are  the  oval  (fenestra 
ovalis)  and  the  round  (fenestra  cochlea  or  rotunda). 
The  oval  opening  is  above,  leads  into  the  vestibule,  and  is 


176  ANATOMY   FOR   NURSES 

closed  by  the  foot  of  the  stirrup  (stapes).  The  round 
opening  is  below,  is  closed  by  the  secondary  tympanic 
membrane,  and  communicates  with  the  cochlea. 

At  the  upper  back  part  the  tympanum  is  continuous 
with  air  cells  in  the  mastoid  part  of  the  temporal  bone 
and  furnishes  a  space  for  a  part  of  the  incus. 

The  three  ossicles  are  the  incus  (anvil),  malleus  (ham- 
mer) and  stapes  (stirrup). 

The  stapes  is  fastened  by  a  long  projection  to  the 
tympanic  membrane.  Its  head  articulates  with  the  in- 
cus which  is  fastened  by  its  short  process  in  the  space 
above  the  tympanum  and  by  its  long  process  to  the 
stirrup.  Hence  if  the  drum  is  moved  it  moves  the  mal- 
leus, which  moves  the  incus  which,  in  its  turn,  moves 
the  stirrup  and  either  presses  it  more  firmly  in  or  draws 
it  away  from  the  fenestra  ovalis.  The  vibrations  of 
the  outer  membrane  are  thus  communicated  across  the 
tympanum  to  the  internal  ear. 

The  internal  ear,  or  labyrinth,  the  point  of  distribu- 
tion of  the  auditory  nerve,  is  a  very  minute  and  irregu- 
lar space  hollowed  out  in  the  petrous  portion  of  the 
temporal  bone  and  lined  by  a  membrane  which  is  the 
exact  counterpart  of  the  space.  Hence  it  consists  of 
an  osseous  and  a  membranous  labyrinth.  This  is  fur- 
ther subdivided  into  the  cochlea  in  front,  the  three  semi- 
circular canals  behind,  and  the  vestibule  connecting  the 
two. 

The  semicircular  canals,  which  are  concerned  in  main- 
taining equilibrium,  are  three  in  number.  The  superior 
an.d  posterior  are  vertical,  the  superior  running  at  right 
angles  to  the  bone  and  the  posterior  parallel  to  its  long 


ORGANS   OF    THE   SENSES  177 

axis.  The  external  is  horizontal.  They  all  communicate 
with  the  vestibule. 

The  cochlea  is  like  a  snail  shell,  or  two  and  a  half 
turns  of  a  conical  screw  thrust  into  a  circular  box.  The 
flanges  of  the  screw  (threads)  would  form  shelf -like 
projections  in  the  box,  ascending  to  the  apex  of  the 
cone,  which  could  be  prolonged  to  the  walls  by  a  mem- 
brane. The  attachment  of  the  membrane  would  split 
the  space  into  an  upper  and  a  lower  coiled  tunnel  each 
running,  like  a  circular  staircase,  around  a  central  col- 
umn. The  central  column  of  the  cochlea  is  called  the 
modiolus,  is  hollow  and  allows  the  nerve  which  lies  in  it 
to  send  its  branches  out  through  the  threads  (laminae)  to 
reach  the  membrane  which  completes  the  two  tunnels. 
The  upper  of  these  coiled  chambers  is  called  scala  vesti- 
buli  and  the  lower  scala  tympani  indicating  the  cham- 
bers with  which  they  communicate. 

The  membrane  stretching  from  the  spiral  laminaa 
(threads)  is  called  the  basilar  membrane  and  supports 
the  organ  of  Corti  in  which  the  terminals  of  the  eighth 
nerve  are  found. 

The  membranous  labyrinth  follows  the  bone  exactly. 
The  part  which  fills  the  vestibule  is  divided  into  two  sacs, 
utricle  for  receiving  the  semicircular  canals  and  saccule 
communicating  with  the  cochlea.  The  membranous  laby- 
rinth is  filled  with  a  fluid  called  endolymph  and  sepa- 
rated from  the  bony  walls  by  another  fluid,  the  peri- 
lifinph. 

THE  LARYNX 

About  half  an  inch  below  the  hyoid  bone  a  promi- 
nence can  be  seen  on  the  midline  of  the  neck  which  is 


178  ANATOMY   FOR    NURSES 

called  the  Adam's  apple.  This  is  the  thyroid  cartilage, 
the  largest  single  element  of  the  larynx,  or  voice  box, 
which  is  made  up  of  cartilages,  ligaments,  muscles, 
nerves,  arteries,  veins  and  lymphatics.  The  chief  car- 
tilages are  the  thyroid,  cricoid  and  arytenoid  (two). 

The  Thyroid  Cartilage 

The  thyroid  cartilage  is  a  hollow  wedge,  base  back- 
ward, open  at  both  ends  and  behind.  It  is  composed 
of  two  quadrilateral  plates  called  alee,  united  in  a  blunt 
angle  in  front  and  expanding  above  and  below  into  proc- 
esses called  cornua.  There  is  a  deep  notch  in  front 
above  which  gives  the  superior  border  a  sinuous  outline. 
The  inferior  border  is  shorter  and  thicker  than  the 
superior  and  its  cornua  are  blunt  and  strong  and 
marked  by  articular  facets  internally.  The  posterior 
border  is  rounded.  The  alag  are  marked  by  oblique 
ridges  for  muscular  attachment. 

The  Cricoid  Cartilage 

The  cricoid  cartilage  is  a  ring,  small  in  front  and 
large  behind  like  a  seal.  BeloAv  it  is  shaped  like  a 
ring  of  the  trachea.  Above  it  slopes  rapidly  upward 
from  in  front  and  has  on  either  side,  a  quarter  of  an 
inch  from  the  midline,  an  oblong  articular  surface  for 
the  arytenoid  cartilages.  On  each  side,  near  the  lower 
border,  is  a  circular  facet  for  the  horris  of  the  thyroid. 
In  the  midline  behind  is  a  vertical  ridge  with  a  depres- 
sion for  muscles  on  each  side. 

The  Arytenoid  Cartilages 

The  arytenoid  cartilages  are  three  sided  pyramids, 
bases  downward,  facing  each  other  on  the  upper  back 


ORGANS   OF    THE   SENSES  179 

part  of  the  cricoid.  The  apex  of  each  is  surmounted  by 
small  corniculate  cartilages.  The  internal  face  is  a 
plane,  the  posterior  and  external  are  concave.  The 
base  presents  an  angle  directed  outward  and  backward 
which  gives  attachment  to  muscles  (the  muscular  proc- 
ess,) and  a  slender  projection  forward  called  vocal 
process  because  the  vocal  cords  are  attached  to  it. 

The  Epiglottis 

The  epiglottis  is  a  thin  leaf -like  cartilage  projecting 
upward  from  the  larynx  just  at  the  base  of  the  tongue. 
Its  small  end  is  below  and  is  bound  to  the  hyoid  bone 
and  thyroid  cartilage  by  bundles  of  ligamentous  fibers. 
In  the  natural  state  it  appears  to  have  its  base  upward, 
due  to  the  folds  of  mucous  membrane  stretching  out 
on  either  side. 

The  Ligaments  of  the  Larynx 

The  various  articular  surfaces  are  bound  together 
by  capsular  ligaments  similar  to  those  holding  bones 
in  apposition  and  the  joints  are  lined  by  synovial  mem- 
brane. Other  bundles  of  fibers  stretch  between  the 
cartilages  and  adjoining  structures.  A  thin  membrane, 
ihyro-hyoid,  thickened  at  each  end  into  a  cord  extends 
from  the  upper  border  of  the  thyroid  to  the  hyoid  near 
its  upper  border.  A  similar  membrane,  the  crico-tkyroid, 
fills  the  gap  between  the  lower  border  of  the  thyroid 
and  upper  border  of  the  cricoid,  which  is  bound  to  the 
upper  ring  of  the  trachea  by  a  thin  membrane. 

Stretching  from  the  vocal  process  of  the  arytenoid  to 
the  back  of  the  thyroid  angle  is  a  long  band  of  elastic 
fibers  which  has  no  part  in  binding  the  cartilages  to- 


180  ANATOMY   FOR   NURSES 

gether  but  is  intended,  by  its  vibrations,  to  produce 
sound.  It  is  called  the  thyro-arytenoid  ligament  or  true 
vocal  cord  and  is  connected  with  the  crico-thyroid  mem- 
brane. 


Hyoid  bone 
I 


Crico-thyroid 

ligament — 

^^_^  r — M.  crico-thyroid 

Cricoid  cartilage— f 


Trachea 


Fig.  19. — Larynx,  anterior  view. 

The  Muscles  of  the  Larynx 

These  are  a  single  muscle,  arytenoideus,  and  four  pairs 
of  muscles,  crico-thyroid,  posterior  crico-arytenoid,  lat- 
eral crico-arytenoid  and  thyro-arytenoid. 

The  arytenoid  fills  the  concavity  on  the  posterior  face 
of  the  arytenoid  cartilages,  stretching  from  one  to  the 
other,  so  that,  when  its  fibers  contract,  it  brings  them  in 
close  apposition. 


ORGANS   OF    THE    SENSES  181 

The  crico-thyroid  is  fan-shaped  and  attached  near  the 
front  of  the  sides  of  the  cricoid  by  one  end  and,  by  the 
other,  to  an  ala  of  the  thyroid  near  its  lower  border  and 
inferior  cornua. 

Its  fixed  point  is  above.  It  pulls  the  front  of  the  cri- 
coid upward,  makes  it  revolve  between  the  inferior  cor- 
nua, and  carries  its  posterior  portion,  and  the  aryte- 
noids  with  it,  backward,  tightening  the  vocal  cords. 

The  posterior  crico-arytenoid  springs  form  the  con- 
cave back  of  the  cricoid,  passes  upward  and  outward  and 
is  inserted  into  the  muscular  process  of  the  arytenoid. 

Its  contraction  pulls  the  vocal  process  inward,  makes 
the  arytenoid  revolve  on  an  axis  through  the  center  of 
its  base,  carrying  the  anterior  (vocal)  process  outward 
and  widening  the  interval  between  the  vocal  cords. 

The  lateral  crico-arytenoid  rises  from  the  upper  border 
of  the  cricoid,  in  front  of  the  arytenoid,  passes  back- 
ward and  is  inserted  into  the  front  of  the  vocal  process. 

It  pulls  the  muscular  process  forward,  rotates  the 
arytenoid  inward  and  narrows  the  space  between  the 
cords,  i.  e.,  it  is  the  antagonist  of  the  posterior. 

The  thyro-arytenoid  rises  from  the  lower  part  of  the 
angle  of  the  thyroid,  runs  backward  and  is  inserted  into 
the  base  and  vocal  process  of  the  arytenoid.  It  lies  paral- 
lel writh  the  vocal  cord  and  is  attached  to  it. 

It  draws  the  whole  arytenoid  forward  and  relaxes  the 
cord.  The  fibers  inserted  into  the  cord  can  relax  one 
portion  and  leave  the  other  tense. 

The  mucous  membrane  Avhich  leaves  the  back  of  the 
tongue,  mounts  over  the  front  of  the  epiglottis,  runs 
down  its  posterior  face  and  enters  the  larynx  which  it 
lines.  It  forms  glosso-epiglottic  folds  from  the  tongue 


182  ANATOMY   FOR   NURSES 


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Fig.  20. — Larynx,  inside  view. 


ORGANS    OF    THE    SENSES  183 

to  the  epiglottis;  a  broad  fold  on  either  side  from  the 
epiglottis  to  the  arytenoids  (aryteno-epiglottidean)  ;  a 
similar  fold  on  either  side  from  the  thyroid  to  the  ary- 
tenoid  (thyro-arytenoid),  the  false  vocal  cords  or  ventric- 
ular folds  and  descends  to  cover  the  true  vocal  cords. 

The  superior  opening  of  the  larynx  slopes  downward 
and  backward;  the  inferior  is  circular  and  passes  di- 
rectly to  the  trachea.  The  superior  communicates  with 
the  mouth,  nose,  and  pharynx.  The  space  above  the 
vocal  cords  is  called  the  vestibule;  that  between  the 
false  and  true  cords  and  between  the  former  and  the 
thyroid,  the  ventricle  and  the  space  between  the  true 
cords  the  rima  glottidis. 


CHAPTER  IX 
HISTOLOGY 

Histology  is  microscopic  anatomy.  It  is  the  study  of 
minute  cells  or  of  tissues  which  have  grown  from  cells, 
and  of  organs  which  are  composed  of  tissues  and  cells. 

THE  CELL 

The  cell  is  the  simplest  form  of  independent  life. 

The  ovum  is  the  name  given  to  the  primary  cell  from 
which  the  creature  is  developed. 

A  cell  is  defined  as  a  "nucleated  mass  of  protoplasm 
endowed  with  the  attributes  of  life." 

Protoplasm — literally  the  first  thing  formed,  is  the 
living  matter  of  which  all  animals  and  vegetables  are 
formed.  It  makes  up  the  mass  of  all  cells  and  of  it  all 
tissues  are  formed. 

The  nucleus  is  the  somewhat  centrally  placed  active 
portion  of  the  cell.  It  seems  to  preside  over  cell 
changes  and  might  be  considered  as  both  the  brain  and 
the  generative  part  of  the  cell. 

The  nucleolus  bears  to  the  nucleus  a  relation  similar 
to  that  which  the  nucleus  bears  to  the  cell. 

The  limiting"  membrane  is  the  thin  and  structureless 
membrane  which  surrounds  the  entire  mass  of  proto- 
plasm called  the  cell. 

Intercellular  cement  is  the  substance  which  binds 
cells  together. 

184 


HISTOLOGY  185 

Growth  and  repair  are  constant  phenomena  of  life. 
Growth  is  an  increase  in  the  number  of  cells  or  in  the 
size  of  tissue.  Repair  is  the  replacement  of  the  worn 
out  or  destroyed  cells  by  IICAV  cells.  Hence  it  is  neces- 
sary that  cells,  like  higher  organisms,  have  the  power 
of  reproduction.  This  process  is  accomplished  by  a  di- 
vision of  the  cell  into  two  bodies,  each  of  which,  at  the 
end  of  the  process,  is  a  complete  cell.  Indirect  division, 
the  most  common  if  not  the  only  form,  is  that  method  by 
which  the  first  changes  occur  in  the  nucleus  and  later  the 
cell  becomes  constricted  into  a  dumb-bell  shape  and  then 
divides.  Direct  division  means  the  constriction  of  the 
whole  cell.  The  change  in  the  nucleus  is  called  mitosis 
or  karyokinesis.  When  this  process  is  completed  the  nu- 
cleus has  divided  into  two  nuclei,  each  in  its  own  part  of 
the  cell  and  each  possessed  of  a  sort  of  magnetic  power 
which  enables  it  to  draw  to  itself  cell  substance  suffi- 
cient to  form  a  new  cell.  Constriction  of  the  body  of 
the  cell  then  takes  place  and  two  cells  are  the  product 
of  the  one  old  cell.  It  is  said  that  this  process  in  man 
requires  about  half  an  hour. 

THE  TISSUES 

Cells  are  either  grouped  together  to  form,  or  are  dif- 
ferentiated into  masses  called,  tissues.  Of  these  we  dis- 
tinguish epithelial,  connective,  muscular  and  nervous 
tissues.  In  addition  to  these  formed  tissues  the  circu- 
lating fluids  blood  and  lymph,  are  to  be  considered. 
Numerous  varieties  of  these  primary  tissues  are  found. 

The  terms  epi  and  endo  thelial  have  been  employed  to 
distinguish  those  layers  of  cells  formed  on  the  surface 


186  ANATOMY   FOR    NURSES 

or  in  open  cavities  from  those  formed  in  vessels  and 
other  closed  cavities,  as  the  serous.  Eiidothelium,  is, 
however,  simply  epithelium  formed  in  these  places. 

Epithelium,  therefore,  may  be  said  to  present  varie- 
ties distinguished  as  endothelium  and  squamous  and 
columnar  epithelium. 

Connective  tissue  presents  the  greatest  number  of  va- 
riations. Under  this  head  are  embraced  white  fibrous, 
yellow  elastic,  adipose  (fatty),  retiform  (lymphoid), 
mucoid,  cartilaginous,  osseous  and  dentine.  That  is  to 
say  that  tissues  varying  as  widely  as  the  soft  fatty  layer 
just  beneath  the  skin  and  the  solid  bone  which  sustains 
the  weight  of  the  body,  are  all  classed  as  connective 
tissues. 

Muscular  tissue  presents  three  varieties,  striated,  un- 
striated  and  cardiac. 

Nervous  tissue  is  without  such  subdivisions. 

The  Distribution  of  Tissues 

Epithelium  is  the  most  widely  distributed  of  all  tis- 
sues. It  covers  the  entire  surface  of  the  body,  where  it 
is  called  epidermis,  enters,  through  the  mouth  and  nose, 
the  digestive  and  respiratory  tracts  which  it  lines 
throughout,  lines  the  genito-urinary  tract,  the  ducts 
and  acini  of  all  glands  and,  as  endothelium,  lines  the 
interior  of  all  blood  and  lymph  vessels  and  the  great 
serous  cavities  of  the  body. 

Connective  tissue,  almost  as  widely  distributed  as 
epithelium,  forms  the  supporting  tissue  beneath  the 
skin  and  serous  and  mucous  membranes,  binds  muscles 
to  bones  and  cartilages,  forms  the  framework  of  the 
ear  (yellow  elastic),  of  the  larynx  (cartilaginous),  sup- 


HISTOLOGY  187 

ports  glandular  organs,  enters  the  walls  of  blood  ves- 
sels and  hollow  viscera  and,  as  bone,  forms  the  frame- 
work of  the  body. 

Muscular  tissue  is  formed  wherever  motion  is  re- 
quired. As  striated  muscular  tissue  it  forms  the  great 
skeletal  muscles  distributed  over  the  body ;  as  nonstri- 
ated  it  forms  part  of  the  walls  of  blood  vessels,  of  the 
digestive  tract,  of  the  genito-urinary  system;  and  as 
cardiac  it  forms  the  great  pump  which  is  the  primary 
force  of  the  circulation. 

Nervous  tissue  is  found  massed  in  the  brain  and 
spinal  cord  and  distributed  throughout  the  body  as 
cranial,  spinal  and  sympathetic  nerves. 

The  circulating  fluids,  Mood  and  lymph,  are  found  in 
every  portion  of  the  body. 

Epithelium 

Epithelium  is  either  squamous  or  columnar,  which  lat- 
ter may  in  its  turn  be  glandular,  cylindrical  or  ciliated. 

Squamous  epithelium  may  be  arranged  as  a.  single 
layer  of  cells,  when  it  is  .called  simple  or  pavement  epi- 
thelium; or  in  many  layers,  when  it  is  said  to  be  strati- 
fied. A  subdivision  of  the  latter  is  called  transitional. 

Endothelium  is  a  simple  epithelium  consisting  of  a 
single  layer  of  cells,  united  by  cement  along  their 
edges,  lining  the  closed  body  cavities.  Openings  called 
stomata  between  the  cells  lead  to  lymph  vessels. 

Squamous  epithelium  consists  of  flat  cells  of  varying 
shape,  united  by  cement,  never  lining  closed  cavities  but 
occurring  in  open  cavities,  as  the  air  sacs  of  the  lungs. 

Columnar  epithelium  consists  of  rod-like  cells  resting 
on  a  basement  membrane,  small  end  towrard  the  mem- 


188  ANATOMY   FOR   NURSES 


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HISTOLOGY  189 

brane,  whose  shape  is  irregular  from  the  pressure  of 
surrounding  cells.  Columnar  epithelium  lines  the  in- 
testinal canal  and  the  glands  connected  with  it. 

Goblet  cells  are  columnar  cells  filled  with  a  substance 
called  mucin  which  is  poured  out  on  the  mucous  sur- 
faces where  they  are  found. 

Glandular  epithelium  is  found  in  the  glands.  The 
cells  are  of  many  sides  from  mutual  pressure. 

Ciliated  epithelium  is  columnar  epithelium  whose 
cells  are  provided  with  lash-like  prolongations,  called 
cilia,  which  produce  motion  independent  of  the  move- 
ment of  the  part,  and  can  thus  extrude  foreign  bodies. 
They  are  especially  useful  in  the  respiratory  tract  and 
in  the  uterus  and  Fallopian  tube. 

Stratified  epithelium  consists  of  many  layers  of  cells 
which  vary  greatly  in  shape  and  consistency.  It  is 
found  on  the  surface  of  the  body  where  it  resists  pres- 
sure. The  cells  vary  from  nearly  formless  horny  scales 
at  the  surface  to  the  soft  irregular  forms  of  the  deeper 
layers. 

Transitional  epithelium  is  a  modification  of  the  strati- 
fied consisting  of  fewer  layers.  It  is  found  in  the 
bladder  and  ureters.  The  superficial  layers  consist  of 
squamous  cells  while  the  deeper  are  elongated  with 
small  ends  embedded  between  cells  of  the  third  layer. 
They  look  like  tadpoles. 

Connective  Tissue 

White  fibrous  tissue,  connective  tissue  proper,  con- 
sists of  parallel  bundles  composed  of  minute  fibrils, 
having  a  wavy  appearance,  bound  together  by  a  trans- 
parent cement  and  having  connective  tissue  corpuscles 


190  ANATOMY   FOR   NURSES 

placed  at  varying  intervals  in  the  bundles.  When 
these  bundles  are  arranged  in  a  broad  sheet  of  loose 
meshwork,  leaving  openings  (areolae)  which  may  con- 
tain some  other  substance,  it  is  called  areolar  tissue. 
Such  tissues  are  the  subcutaneous,  siibserous  and  other 
areolar  tissues.  When  the  areolae  contain  fat  globules 
the  combination  of  fat  and  fibrous  tissue  is  called  adipose 
tissue.  When  the  fibrils  are  gathered  into  compact 
bundles  with  few  corpuscles  they  form  tendons,  or  are 
spread  out  into  aponeuroses  or  the  great  investing 
fascias. 

Retiform,  or  lymphoid,  or  adenoid,  tissue  is  a  very  fine 
connective  tissue  forming  the  framework  of  mucous 
membranes.  It  has  many  branched  connective  tissue 
cells  and  the  cement  has  nearly  disappeared. 

Yellow  elastic  tissue  is  composed  of  coarse  branching 
fibers  which  anastomose  and  have  a  tendency  to  curl 
up.  They  are  elastic  \vhile  white  fibrous  is  not.  They 
are  found  in  the  ligamenta  subflava  of  the  spinal  col- 
umn and  in  but,  few  other  places  in  the  human  body. 


CARTILAGE 

Cartilage  is  permanent  when  it  remains  unossified 
through  life  and  temporary  when  it  is  replaced  by  bone. 
The  latter  forms  the  greater  part  of  fetal  skeleton.  The 
subdivisions  are  hyaline,  the  most  widely  distributed, 
white  fibro  and  yellow  elastic. 

Hyaline  cartilage  is  found  chiefly  on  the  articular  sur- 
face of  bones  and  in  the  rings  of  the  trachea.  It  is  sur- 
rounded by  a  fibrous  vascular  membrane,  the  perichon- 
drium,  except  in  the  joints.  It  consists  of  a  structureless 


HISTOLOGY 


191 


Fig.  22. — Human  cartilage  cells. 


Fig.    23. — Hyaline  cartilage. 


192  ANATOMY   FOR   NURSES 

or  slightly  granular  ground  work  with  cells  embedded 
and  usually  arranged  in  pairs.  It  has  no  blood  vessels 
or  nerves  and  derives  its  nourishment  from  the  perichon- 
drium.  Its  ground  substance  was  probably  white  fibrous 
tissue. 

White  fibrocartilage  is  partly  cartilage  but  mainly 
white  fibrous  tissue.  It  is  found  in  the  intervertebral 
disks  chiefly. 

Yellow  elastic  cartilage  is  partly  cartilage  but  is 
mainly  composed  of  yellow  elastic  fibers.  It  is  found  in 
the  ear,  epiglottis,  eustachian  tube,  etc. 

BONE 

Bone  is  either  compact,  as  in  the  shafts  of  long  bones, 
or  spongy,  as  in  the  irregular  bones  and  the  extremities 
of  long  bones.  All  bone  is  modified  connective  tissue, 
the  fibrils  being  replaced  by  minerals,  chiefly  phos- 
phates. 

The  shaft  of  a  long  bone  may  be  considered  as  a  cen- 
tral large  canal,  or  tunnel,  running  the  length  of  the 
shaft,  whose  surrounding  walls  are  composed  of  minute 
tunnels  parallel  with  the  central  canal  arranged  in 
layers  (lamellae)  perforated  by  minute  channels  (cana- 
liculi)  which  pierce  each  lamella  making  up  the  sys- 
tem. These  small  tunnels  or  tubes  are  called  Haversian 
canals.  Each  Haversian  canal  with  its  surrounding 
lamellae  and  canaliculi  constitutes  a  Haversian  system. 

At  intervals  the  canaliculi  are  enlarged  to  form  la- 
cunae, containing  bone  corpuscles.  A  vast  number  of 
Haversian  systems,  arranged  like  bunches  of  small 
tubes  around  a  large  central  tube,  go  to  make  up  a 


HISTOLOGY 


193 


long  bone.  The  Haversian  canals  branch  and  com- 
municate with  each  other  at  intervals,  so  the  blood  ves- 
sels they  contain  may  communicate.  Between  the 


Fig.  24. — White  fibrocartilage. 

Haversian   systems,   filling  in  the   irregular  intervals, 
are  partial  lamellae  with  canaliculi. 

Each  Haversian  canal  contains  an  arteriole,  venule, 
lymph  channel  and  a  nerve  filament.  These  run 
through  the  canaliculi,  piercing  the  lamellae  in  every 


ANATOMY  FOR  NURSES 

direction,  making  free  anastomoses  in  each  Haversian 
system;  but  two  adjacent  Haversian  systems  do  not 
communicate  with  each  other. 

Spongy  bone  has  the  same  arrangement  of  lacuna? 


Fig.  25. — Elastic  cartilage. 

and   canaliculi   as   compact   bone,    but   no    Haversian 
canals. 

Development  of  Bone. — With  the  exception  of  the 
bones  of  the  face  and  the  cranial  vault,  bones  appear 
in  the  embryo  as  cartilage.  There  follows  a  process 


HISTOLOGY 


195 


of  enlargement  of  the  cartilage  cells  and  arrangement 
in  rows.  Osseous  deposits  take  place  in  the  matrix  and 
processes  are  pushed  in  from  the  perichondrium  car- 
rying bone  cells  and  blood  vessels.  The  vessels  lie  in 


/ 


Fig.  26. — Nucleated  bone  cells,  etc. 

the  future  Haversian  canals ;  their  branches  in  the  cana- 
liculi,  bone  deposits  are  laid  down  between  the  canali- 
culi  to  constitute  the  future  lamellae,  and  this  process 
is  continued  until  the  firm  bone  is  formed. 

Blood  Vessels. — It  follows  from  what  has  been  said 
of  development  that  blood  vessels  enter  compact  bone 


196 


ANATOMY   FOR   NURSES 


from  the  periosteum,  run  in  the  Haversiau  canals,  di- 
vide where  the  canals  divide,  and  give  off  numerous 
minute  branches  to  the  Haversian  systems.  The  blood 
to  the  central  marrow  usually  comes  from  a  single  large 
vessel  which  enters  through  a  foramen  in  the  shaft, 
pierces  to  the  marrow  cavity  and  there  breaks  up  into 


Fig.  27. — Transverse  section  of  compact  tissue  of  bone  greatly  magnified. 

ascending  and  descending  branches.  The  return  circu- 
lation comes  back  through  the  same  foramen  and  the 
nerve  enters  it  with  the  artery. 

Marrow. — This  substance  not  only  fills  the  tubes  of 
the  long  bones  but  extends  into  the  cancellous  tissue 
of  their  extremities  and  into  the  interstices  of  the  ir- 


HISTOLOGY  197 

regular  bones.  In  the  long  bones  it  is  called  yellow  mar- 
row and  contains  about  96  per  cent  fat.  In  cancellous 
bone  it  is  called  red  marrow  and  consists  of  25  per  cent 
of  all  solids,  a  small  proportion  of  which  is  fat,  and 
75  per  cent  Avater. 


Fig.   28. — Section  parallel  to  the  surface   from  the  shaft   of  the  femur. 

Periosteum  is  the  membrane  which  surrounds  bone. 
It  is  made  up  of  connective  and  elastic  tissue,  the  latter 
forming  the  deep  layer,  contains  some  fat  and  carries 
the  network  of  blood  vessels  and  nerves  which  surround 
the  bone. 


198  ANATOMY    FOR   NURSES 

MUSCLE 

Muscle  fiber  is  striated,  nonstriated  or  cardiac,  a  va- 
riety resembling  striated. 

Striated  muscle  fiber  is  the  bulkiest  tissue  in  the 
body,  being  the  chief  constituent  of  the  red  skeletal 
muscles. 

Nonstriated  muscle  fiber  is  found  in  all  those  organs 
where  the  contractile  power  of  muscle  is  required  but 
where  its  action  must  not  be  interfered  with  by  the 
conscious  will.  The  hollow  intestinal  canal,  the  uterus, 
bladder,  blood  and  lymph  channels  are  its  chief  seats. 

Cardiac  muscle  fiber,  as  its  name  indicates,  is  found 
only  in  the  heart.  It  is  striated  but  branched. 

Voluntary,  or  striated,  muscle  cut  parallel  to  the 
fibers,  is  marked  by  elongated  dark  lines  crossed  at 
regular  intervals  by  light  transverse  lines.  Cross  sec- 
tions show  these  bundles  on  end  as  polygonal  areas 
called  Cohnheim's  fields. 

Each  fibril  consists  of  an  elongated  mass  of  contrac- 
tile substance,  tapering  at  either  end  to  join  the  next 
mass,  contained  in  a  delicate  sheath,  the  sarcolemma. 
A  number  of  fibrils  are  bound  together  by  delicate  con- 
nective tissue,  the  perimysium,  forming  fasciculi;  while 
a  complete  muscle  is  formed  by  binding  together  a  vast 
number  of  fasciculi  by  a  thicker  connective  tissue  cover- 
ing, called  the  epimysium. 

When  muscle  is  united  to  tendon  the  contractile  ele- 
ment and  sarcolemma  round  off  into  a  blunt  point  and 
the  sarcolemma  is  cemented  to  the  tendon. 

Blood  vessels  are  very  numerous  in  striated  muscle. 


HISTOLOGY  199 

Cardiac  Muscle 

Cardiac  muscle  fibers  are  shorter  and  smaller  than 
those  of  skeletal  muscles,  branch  and  inosculate  with 
each  other,  and  have  no  distinct  sarcolemma. 

Nonstriated  Muscle 

Involuntary  or  nonstriated  muscle  fibers  consist  of 
elongated  or  spindle-shaped  cells,  each  containing  an 
elongated  nucleus,  marked  by  slight  longitudinal  stria- 
tions.  They  are  held  together  by  a  transparent  ce- 
ment and  form  broad  sheets  arranged  in  various  ways, 
i.  e.,  running  both  circularly  and  longitudinally  in  the 
intestine,  radiating  in  the  stomach,  etc.,  and  intimately 
connected  with  the  fibrous  tissue  of  the  various  organs 
in  which  these  muscle  fibers  occur. 

THE  NERVOUS  SYSTEM 

The  nervous  system  consists  of  nerve  cells,  nerve 
fibers,  connective  tissue,  and  neuroglia  and  nerve  ter- 
minals. 

Nerve  cells,  usually  called  ganglion  cells,  are  of  many 
shapes  and  sizes.  They  have  large,  round  nuclei,  with 
nucleoli  and  their  protoplasm  contains  pigment.  These 
cells  have  one  or  many  processes  springing  from  them 
and  are  described  as  nni-,  hi-  or  multipolar.  Each  cell 
has  one  process  called  the  axis  cylinder  process.  The 
other  processes  divide  and  form  networks.  A  ganglion 
cell  with  its  axis  cylinder  process  is  called  a  neurone. 

Nerve  fibers  may  be  medullated,  or  white,  or  non- 
medullated,  or  gray.  Each  fiber  consists  of  a  central 
portion,  the  axis  cylinder,  an  enveloping  sheath,  largely 


200  ANATOMY    FOR    NURSES 

fatty  called  the  white  substance  of  Schwann  or  medullary 
sheath,  and,  surrounding  this,  an  envelope  of  connective 
tissue,  the  neurilemma.  At  intervals  the  neurilemma  is 
constricted  so  as  to  reach  the  axis  cylinder.  These  con- 
strictions are  called  nodes  of  Ranvier. 

A  collection  of  a  number  of  parallel  nerve  fibers  bound 
together  by  connective  tissue  called  endoneurium,  forms 
a  funiculus.  Many  parallel  funiculi,  bound  together  by 
another  layer  of  connective  tissue,  the  perineurium,  form 
a  nerve  trunk,  which  is  surrounded  by  a  connective  tis- 
sue sheath  called  the  epineurium.  The  epineurium  car- 
ries the  blood  vessels  of  the  nerves  and  dips  in  to  blend 
with  the  perineurium. 

Neuroglia  is  a  special  form  of  very  delicate  connec- 
tive tissue,  connected  with  the  pia  mater,  which  fur- 
nishes a  supporting  frameAVork  for  the  brain.  Large 
numbers  of  fibrils,  derived  from  neuroglia  cells  inter- 
lace and  form  a  network  through  the  brain  and  cord. 

Nerve  terminals  are  of  various  forms.  Some  sen- 
sory nerves  lose  their  medullary  sheaths,  divide  into 
many  fibrils  and  have  free  endings  between  epithelial 
cells  or  in  connective  tissue.  Others  end  in  the  tactile 
corpuscles  of  the  skin,  in  the  Pacinian  bodies,  in  end 
plates  in  striated  muscle,  etc. 

The  Central  Nervous  System 

The  essential  function  of  nerves  is  to  conduct  impul- 
ses between  the  brain  and  the  periphery ;  that  of  nerve 
cells  to  receive  or  to  instigate  such  impulses  or  impres- 
sions. The  nerve  cells  are,  therefore,  accumulated  in 
large  masses  in  the  brain  and  spinal  cord,  Avhich  is  an 
intermediate  link  between  brain  and  periphery. 


HISTOLOGY  201 

The  Spinal  Cord 

The  spinal  cord  is,  on  cross  section,  oval  in  form  and 
partly  divided  by  anterior,  and  posterior  median  fissures 
into  two  similar  halves.  The  exterior  is  composed  of  me- 
dnllated  fibers  and  the  interior  of  a  central  gray  mass 
arranged  like  an  irregular  capital  letter  H,  or  like  two 
crescents  with  their  convexities  back  to  back,  large  in 
front,  small  and  long  behind,  and  held  together  by  a 
transverse  bar.  These  elongations  are  called  the  an- 
terior and  posterior  horns  of  the  gray  matter  of  the  cord. 
From  these  horns  the  spinal  nerves  spring,  the  motor 
roots  from  the  anterior  and  the  sensory  from  the  pos- 
terior horns.  The  exit  of  these  roots  through  the  white 
matter  leaves  a  chain  of  minute  openings  which  divides 
the  cord  into  three  columns,  anterior,  posterior,  and 
lateral,  the  first  and  second  bordering  on  the  fissures 
of  the  same  name  and  the  third  betAveen  the  other  two. 
Further  subdivision  into  columns  is  made  by  tracing  the 
fibers  into  the  medulla,  the  next  step  toward  the  brain. 

Except  in  arrangement  of  parts,  the  gray  matter 
being  largely  on  the  surface,  brain  substance  does  not 
differ  materially  from  that  of  the  cord.  The  nerve 
fibers  are  medullated  and  without  neurilemma  in  the 
main.  There  are  five  layers  of  the  surface  gray  matter. 
The  pia  mater  lies  next  the  gray  matter  and  sends 
blood  vessels  into  the  interior  of  the  brain  substance. 

THE  BLOOD 

Blood  contains  solid  bodies  called  corpuscles,  which 
are  either  circular,  biconcave  disks,  the  red  blood  cor- 
puscles, or  nearly  spherical,  often  granular,  colorless 
bodies  called  ivhite  blood  corpuscles  or  leucocytes. 


202  ANATOMY   FOR   NURSES 

Bed  corpuscles  are  about  1/3200  inch  in  diameter, 
and  number  about  5,000,000  to  the  cubic  millimeter  of 
blood.  They  are  oxygen  carriers. 

White  corpuscles  vary  in  size  up  to  nearly  double 
the  diameter  of  the  red.  They  vary  also  in  number. 
Normally  there  are  from  five  to  ten  thousand  to  the 
cubic  millimeter  of  blood. 

White  cells  are  capable  of  movement  by  putting  out 
projections  called  pseudopodia  into  which  the  remainder 
of  the  cell  may  flow.  They  are  of  great  importance  in 
inflammation.  Pus  is  largely  composed  of  dead  white 
cells.  White  cells  contain  nuclei  and  are  described  as 
leucocytes  and  lymphocytes. 

There  are  certain  other  corpuscular  elements  in  the 
blood,  about  one-fourth  the  size  of  the  red  corpuscles, 
known  as  Hood  plates. 

The  coloring  matter  of  the  blood  is  called  hemoglobin. 
It  may  be  crystalized  from  the  blood.  It  gives  the  red 
cells  their  power  of  carrying  oxygen. 

THE  SKIN 

The  skin  is  made  of  two  layers,  the  epidermis  or  scarf 
skin  and  the  derma,  corium,  or  true  skin. 

The  epidermis  is  divided  into  five  layers  of  which 
the  first  and  second  are  called  the  horny  layer  and  are 
made  up  of  more  or  less  worn-out  cells,  like  dandruff, 
which  is  derived  from  the  first  layer. 

The  remaining  three  layers  constitute  the  Malpighian 
layer,  or  rete  mucosum.  The  cells  of  these  three  layers 
become  more  distinct  in  form  until,  in  the  deepest  layer, 
they  are  columnar  in  shape  and  carry  the  pigment  of 
colored  races.  * 


HISTOLOGY  203 

The  corium,  derma  or  true  skin  is  made  up  of  dense 
fibrillated  connective  tissue  arranged  in  minute  eleva- 
tions, papillce,  which  indent  the  epidermis  and  carry  the 
blood  vessels  and  nerves  of  the  skin.  The  latter  often 
terminate  in  tortuous  structures  called  tactile  corpuscles. 

Beneath  the  skin  there  is  a  layer  of  connective  tissue 
and  fat  in  which  the  superficial  bolod  vessels  and  nerves 
run,  called  the  subcutaneous  connective  tissue. 

Connected  with  the  skin  are  the  hairs,  sebaceous  and 
sudoriferous  glands  and  the  nails.  These  are  called  the 
appendages  of  the  skin. 

THE  CIRCULATORY  SYSTEM 

The  constituents  of  the  circulatory  system  are  the 
heart,  arteries,  arterioles,  capillaries,  venules,  and  veins. 

The  heart  is  a  hollow  muscle  covered  on  its  exterior 
by  a  serous  membrane,  the  pericardium,  which  is  a 
single  layer  of  flat  endothelial  cells  on  a  fibroelastic 
membrane.  Beneath  this  is  a  layer  of  connective  tissue 
and  fat,  particularly  along  the  blood  vessels,  similar  to 
the  subcutaneous  connective  tissue  and  fat. 

The  connective  tissue  is  continuous  with  that  between 
the  muscle  fibers.  Next  comes  the  cardiac  muscle 
fibers  and  then,  lining  the  cavity  of  the  heart,  a  fibro- 
elastic membrane  supporting  a  single  layer  of  flat  en- 
dothelial cells,  the  endocardium.  The  valves  of  the  heart 
are  duplications  of  the  endocardium. 

Blood  vessels  are  channels  conveying  blood  from  and 
to  the.  heart.  With  one  exception  arteries  carry  arterial 
blood  away  from,  and  veins  carry  venous  blood  to,  the 
heart.  Arterioles  are  small  arteries  and  venules  small 


204  ANATOMY    FOR    NURSES 

veins.  Capillaries  form  the  connecting  link  between  the 
arterial  and  venous  system. 

All  blood  vessels  are  lined  with  flat  eiidothelial  cells, 
cemented  by  their  edges,  continuous  with  the  endocar- 
dium, and  their  walls  are  composed  of  nonstriated  mus- 
cular, yellow  elastic  and  white  fibrous  connective  tissues, 
which  vary  in  proportion  with  the  size  of  the  vessels. 
In  large  arteries  the  yellow  elastic  preponderates,  while 
in  arterioles  the  muscular  fiber  is  in  excess.  Arteries 
consist  of  three  coats  known  from  within  the  lumen 
as  intima,  media  and  adventitia. 

The  intima  is  mainly  endothelium. 

The  media  is  chiefly  of  muscular  and  yellow  elastic 
fibers. 

The  adventitia  is  nearly  all  white  fibrous  tissue  with 
some  yellow  elastic. 

The  capillaries  are  made  up  of  flat  eiidothelial  cells 
held  together  by  cement  substance.  In  the  venules  the 
muscular  and  elastic  elements  begin  to  be  apparent  and 
in  the  veins  the  adventitia  appears.  All  the  coats  of 
veins,  except  the  intima,  are  thinner  than  the  same  coats 
in  the  arteries.  Valves  in  the  veins  are  semilunar  redu- 
plications of  the  intima. 

Lymph  channels  are  identical  in  structure  with  veins, 
but  their  walls  are  much  thinner. 


THE  SPLEEN 

The  spleen  is  a  ductless  organ  whose  essential  tissue, 
the  splenic  pulp,  is  arranged  around  the  blood  vessels. 
The  organ  is  surrounded  by  a  fibrous  capsule,  with  a 


HISTOLOGY  205 

layer  of  nonstriated  muscle  tissue  beneath  it,  which 
sends  bands,  or  partition  walls,  throughout  the  organ, 
which  subdivide  to  form  smaller  compartments  to  con- 
tain the  pulp.  The  capillaries  do  not  unite  to  form 
venules  but  empty  into  sponge-like  venous  spaces, 


i       &ff 

y 


Fig.  29. — Vertical  section  of  human  spleen  (modified  from  Kolliker), 
low  power.  t,  trabeculae;  m,  Malpighian  corpuscles;  b,  injected  arterial 
twigs;  s.p.,  spleen  pulp.  The  clear  spaces  are  the  venous  sinuses. 


through  which  the  blood  niters  to  finally  enter  small 
veins  which  unite  to  form  the  splenic  vein.  Many  of 
the  arteries  are  surrounded  by  nodules  of  adenoid  tis- 
sue called  Malpighian  bodies. 


206 


ANATOMY   FOR   NURSES 

GLANDS 


A  gland  is  an  organ  whose  cells  manufacture,  from 
the  blood,  something  to  be  utilized  in  or  excreted  from 
the  body.  The  simplest  form  of  gland  would,  therefore, 
be  a  duct  or  tube  to  convey  away  secretion,  the  paren- 
chyma, or  cell  to  form  the  secretion,  and  a  nerve  and 
blood  supply. 


> 


§0? 
J^fe. 

' 


Fig.  30. — Cross  section  of  pancreatic  tubule  (modified  from  Sobotta). 

Glands  may  be  simple  tubular,  coiled  tubular,  as  in 
sweat  glands,  branched  tubular,  or  acinous. 

Acinous  glands  consist  of  a  single  tube  which  becomes 
clubbed  at  its  extremity  and  partially  divided  into 
many  compartments  called  acini  or  alveoli.  A  number 
of  acini,  held  together  by  delicate  connective  tissue,  form 
a  lobule;  several  lobules  may  be  bound  up  in  the  same 
way  to  form  a  lobe,  and  all  the  lobes,  enveloped  in  a 


HISTOLOGY  207 

capsule  of  connective  tissue,  form  a  compound  acinous 
gland.  This  arrangement  gives  rise  to  a  many-branched 
duct  to  convey  the  secretion  from  the  gland.  All  the 
branches  from  one  lobule  unite  to  form  an  intralobular 
duct,  which  unites  with  the  ducts  of  adjacent  lobules 
to  form  an  interlobular.  duct,  running  between  the 
lobules ;  and  these,  in  turn,  unite  to  form  the  main  duct 
of  the  gland,  as  in  the  duct  of  Wirsung  of  the  pancreas 
or  Stensoii's  duct  of  the  parotid. 

The  salivary,  buccal  and  mammary  glands  and  the 
pancreas  are  all  compound  racemose  or  acinous  glands. 

Slight  differences  in  structure  are  found  in  the  sub- 
lingual,  a  mucous  gland,  and  the  submaxillary,  a  mixed 
gland,  which  differentiate  them  from  the  pure  serous 
glands  like  the  parotid;  but  the  general  type  is  the 
same.  In  all  the  blood  vessels  and  nerves,  with  which 
they  are  abundantly  supplied,  follow  the  branches  of 
the  duct  until  it  enlarges  into  alveoli  which  are  sur- 
rounded by  the  vessels,  bringing  their  contents  into 
closest  contact  with  the  active  cells  of  the  glands.  The 
dividing  and  supporting  bands  of  connective  tissue  are 
all  derived  from  the  capsule  or  envelope. 

The  Liver 

The  liver,  the  largest  of  the  glandular  organs,  is  sur- 
rounded by  a  dense  connective  tissue  envelope,  the 
capsule  of  Glisson,  covered  by  peritoneum,  which  sends 
branching  septa  throughout  the  organ  subdividing  it 
into  numberless  minute  subdivisions  called  lobules.  Every 
lobule  is  made  up  of  liver  cells,  the  parenchyma,  and 
connected  with  four  channels  or  vessels,  two  of  which 
convey  something  to  and  two  something  from  the  lobule. 


208 


ANATOMY   FOR   NURSES 


b.d. 
h.a. 


Fig.   31. — Portion    of    transverse   section    of   human   liver.      X.    100      h.a., 
hepatic  artery;  v.c.,  intralobular  vein;  v.p.,  interlobular  vein;  b.d.,  bile  duct. 


HISTOLOGY  209 

The  whole  object  is  to  put  the  liver  cells  in  intimate  as- 
sociation with  the  blood  and  bile  vessels.  Hence  the 
structure  of  the  liver  can  be  understood  only  when  the 
arrangement  of  these  vessels  is  comprehended.  The 
vessels  run  in  the  bands  of  connective  tissue  which  at 
once  support  the  lobules  and  separate  them  from  each 
other. 

The  hepatic  artery  and  the  portal  vein  carry  blood  into 
the  liver.  The  hepatic  veins  and  the  bile  duct  carry  blood 
and  bile  respectively  from  the  liver. 

The  artery,  portal  vein,  and  bile  duct  enter  the  liver 
through  the  transverse  fissure  and  at  once  begin  to 
divide  into  small  and  smaller  branches  until,  finally,  a 
very  minute  branch  of  each  is  found  in  the  connective 
tissues  which  surround  each  lobule.  From  these  small- 
est vessels  capillaries  are  given  off.  which  penetrate  the 
lobules  between  the  liver  cells.  The  cell  are  now  in  con- 
tact with  (a)  arterial  capillaries  carrying  blood  to  nour- 
ish the  liver;  (b)  portal  capillaries  carrying  blood  to  be 
acted  on  by  liver  cells;  (c)  bile  duct  capillaries  to  pick 
up  the  secretion  of  the  liver  cells;  and  (d)  hepatic  capil- 
laries to  take  up  the  bile  free  blood  and  convey  it  to  the 
center  of  the  lobule  where  these  capillaries  empty  into, 
or  form  an  intralobular  venule  which  is  the  beginning 
of  the  hepatic  veins.  The  direction  of  the  current  in 
the  portal  and  arterial  capillaries  is  toward  the  lobule, 
in  the  hepatic  and  bile  capillaries,  away  from  the 
lobule.  The  portal,  arterial  and  bile  vessels  lie  between 
the  lobules  and  are  interlobular.  The  interlobular  veins 
unite  beyond  the  lobules  into  veins  called  sublobular. 
Within  the  lobules,  packed  between  the  capillaries,  lie 
the  liver  cells. 


210  ANATOMY  FOR   NURSES 

THE  DIGESTIVE  TRACT 

The  canal  beginning  at  the  mouth  and  ending  at  the 
anus  is  subdivided  into  mouth,  pharynx,  esophagus, 
stomach,  small  and  large  intestines. 

The  Mouth,  Pharynx,  and  Esophagus 

The  mouth  is  lined  by  a  mucous  membrane  which  con- 
sists of  stratified  epithelium. 

The  tongue,  which  consists  chiefly  of  striated  muscle, 
is  marked  on  its  upper  surface  by  a  large  number  of  pa- 
pillae which  are  distinguished  from  each  other  by  being 
filiform  or  conical  in  shape,  fungiform,  having  a  con- 
stricted base,  or  circumvallate,  which  are  fungiform  in 
shape  but  surrounded  by  a  depression  with  a  wall-like 
elevation.  They  are  located  at  the  back  of  the  tongue 
Taste  buds  are  flask-shaped  collections  of  epithelial  cells 
around  the  circumvallate  papillae  and  at  other  places 
on  the  tongue. 

The  teeth  are  calcareous  structures,  divided  into  an 
exposed  part  called  the  crown,  a  constricted  portion,  the 
neck  and  a  root  or  roots  embedded  in  the  alveolus  or 
socket  of  the  jaw.  The  crown  is  covered  by  the  hardest 
structure  in  the  body,  the  enamel.  Beneath  this  is  a  layer 
derived  from  connective  tissue  called  dentine,  not  so  hard 
as  enamel,  pierced  by  radiating  canals  in  which  vessels 
and  nerves  lie,  surrounding  a  pulp  chamber  which  con- 
tains the  main  vessels,  nerves  and  lymphatics  of  the  tooth, 
bound  together  by  connective  tissue  and  forming  the 
pulp. 

The  tonsils  are  large  collections  of  lymphoid  tissue 
containing  many  lymph  follicles.  The  surface  and 


HISTOLOGY  211 

crypts  of  the  tonsils  are  covered  by  stratified  squamous 
epithelium. 

The  pharynx  above  the  soft  palate  is  covered  by 
ciliated  columnar  epithelium;  below  the  palate,  by 
stratified  squamous  epithelium. 

The  esophagus  is  lined  by  stratified"  squamous 
epithelium  resting  on  connective  tissue,  the  two  form- 
ing the  mucous  coat.  External  to  this  are  the  mus- 
cularis  mucosa,  submucosa  and  muscular  coats  which 
are  striated  in  the  upper  third  and  unstriated  in  the 
remainder. 

The  Stomach  and  Intestines 

The  stomach  and  intestines  are  made  up  of  a  mucous 
coat,  which  consists  of  epithelial  lining,  mucosa  and 
muscularis  mucosa  which  is  a  very  thin  layer  of  non- 
striated  muscular  fibers  separating  the  mucous  mem- 
brane and  the  submucosa.  The  latter  is  a  layer  of 
loose  areolar  tissue,  corresponding  to  subcutaneous 
connective  tissue,  which  connects  the  muscular  and 
mucous  coats  and  carries  the  larger  vessels,  nerves, 
and  lymphatics. 

The  muscular  coat  is  made  up  of  an  inner  circular 
and  an  outer  longitudinal  layer  of  nonstriated  muscle. 
External  to  this  is  a  subserous  layer  of  connective  tissue 
and  then  the  partial  or  complete  peritoneal  or  serous 
coat. 

The  mucous  coat  may  be  thrown  into  folds  called 
rugae  in  the  stomach  and  valvulce  conniventes  in  the 
small  intestines,  which  greatly  increase  the  extent  of 
its  surface. 

The  mucosa  of  the  stomach  is  marked  by  minute  de- 


212  ANATOMY  FOR   NURSES 

pressions,  gastric  tubules  or  glands,  which  produce  the 
gastric  juice.  Those  in  the  cardiac  end  are  called 
peptic  glands;  while  the  pyloric  are  situated  in  the 
small  end  of  the  organ. 

The   intestines  are   formed   on   the   above   plan,   the 


Fig.  32. — 'Injected  lacteal  vessels  in  two  villi  of  human  intestine.  (Teich- 
mann.)  X  100.  L,acteals  filled  with  white  substance  and  blood  vessels 
with  dark. 

longitudinal  muscular  coat  of  the  large  being  gathered 
into  three  bundles  instead  of  forming  a  thin  layer 
around  the  circumference  of  the  canal. 

The  mucosa,  of  the  small  intestine  is  studded  by  in- 
numerable elevations,  villi,  separated  by  depressions 
of  similar  minuteness,  the  crypts  of  Lieberkiihn,  which 


HISTOLOGY  213 

correspond  to  the  tubules  of  the  stomach.  Every  villus 
has  passing  into  it  an  arterial  capillary  and  from  it  a 
venous  capillary  and  a  lacteal.  The  first  carries 
blood  to  nourish  the  villus,  the  second  carries  the 
return  circulation  containing  the  usual  waste  products 
plus  the  products  of  digestion,  while  the  third  conveys 
certain  blood  products,  chiefly  fat,  into  the  lymph 
spaces  and  channels  in  the  submucosa  and  thence  into 
the  larger  lymphatics  of  the  mesentery.  The  cells 
lining  the  villi  secrete  a  part  of  the  intestinal  fluid— 
succus  entericus — while  the  remainder  is  formed  by 
glands  of  Brunner  located  below  the  crypts  of  Lieber- 
kiihn  and  opening  into  the  crypts. 

Connected  with  the  lymphatic  plexus  in  the  submu- 
cosa are  lymph  nodules  improperly  called  glands. 
These  are  sponge-like  bodies  through  which  the  lymph 
filters,  its  circulation  being  always  in  the  direction  of 
the  venous  blood. 


THE  KIDNEY 

The  kidney  is  surrounded  by  a  fibrous  capsule  wrhich 
sends  delicate  septa  throughout  the  organ.  Its  blood 
vessels,  nerves,  and  duct  enter  or  leave  at  the  hilum. 
As  its  function  is  to  extract  the  urinary  solids,  and 
water  to  hold  them  in  solution,  from  the  blood,  its  es- 
sential structure  is  that  of  a  set  of  capillaries  so  ar- 
ranged that  they  will  be  surrounded  by  kidney  cells, 
set  in  tubes,  which  can  remove  the  urine  from  the 
blood  and  pour  it  into  the  tube.  If  the  kidney  be  split 
along  its  outer  border,  it  will  be  seen  to  consist  of  a 
dark  outer  and  a  lighter  inner  portion,  distinguished 


214 


ANATOMY   FOB   NURSES 


Fig.   33. — Diagrammatic  representation  of  the  course  of  the  uriniferous 
tubules  and  the  kidney  vessels. 


HISTOLOGY  215 

as  cortical  and  medullary.  In  the  cortical  (outer)  por- 
tion the  work  of  removing  urine  from  the  blood  is 
in  the  main  performed,  while  the  medullary  part  is 
largely  occupied  by  minute  tubules  conveying  the 
urine  to  the  excretory  duct — ureter. 

If  the  small  arterioles  be  traced  to  the  cortex  they 
will  be  found  to  terminate  in  a  curious  tuft  of  capil- 
laries called  Malpigkian  bodies  or  glomeruli;  and  each 
tuft  is  surrounded  by  the  expanded  end  of  a  tubule, 
Bowman's  capsule,  whose  lining  of  flat  epithelial  cells 
is  reflected  over  the  glomerulus.  The  small  tubule  lead- 
ing from  Bowman's  capsule,  after  winding  about  as 
the  first  convoluted  tubule,  runs  a  short  distance  into 
the  medullary  portion  and  then  turns  upward  and  re- 
enters  the  cortical  area,  the  U-like  loop  thus  formed 
being  known  as  Henle's  loop,  while  the  tortuous  part 
which  reenters  the  cortex  is  the  second  convoluted  tu- 
bule. After  the  formation  of  the  glomeruli  from  an 
afferent  arteriole,  these  capillaries  contract  to  form  an 
efferent  arteriole  which  penetrates  Bowman's  papsule 
and  breaks  up  into  a  second  series  of  capillaries  in  the 
region  of  the  convoluted  tubules.  From  these  last  the 
venous  capillaries  are  formed  and  remove  the  urine- 
free  blood  from  the  kidneys.  The  blood  has  been 
brought  in  contact  with  the  kidney  cells  at  two  points, 
i.  e.,  in  Bowman's  capsule  around  the  Malpighian  tufts 
and  in  the  convoluted  tubules  by  the  second  series  of 
capillaries.  The  second  convoluted  tubule  now  runs  a 
nearly  direct  course  into  the  pyramids  from  which 
the  urine  drops  into  a  calyx,  the  beginning  of  the  ure- 
ter. Several  calices  unite  to  form  an  infundibulum 


216  ANATOMY    FOR    NURSES 

and  the  three  infundibula  unite  to  form  the  pelvis  of  the 
ureter  which  contracts  to  the  ureter  proper. 


ORGANS  OF  RESPIRATION 

The  organs  of  respiration  are  the  larynx,  trachea, 
bronchi,  and  lungs.  The  function  of  these  organs  is  to 
effect  an  exchange  of  gases  in  the  blood  and  to  produce 
articulate  sound. 

The  larynx,  trachea,  and  bronchi  have  a  framework  of 
hyaline  cartilage,  except  the  epiglottis  which  is  yellow 
elastic,  and  each  is  lined  by  epithelium  which  is  strati- 
fied squamous  over  the  epiglottis  and  upper  third  of 
the  larynx  and  stratified  columnar  and  ciliated  else- 
where. Next  to  the  epithelium  lies  the  mucosa  or  in- 
ternal fibrous  coat,  containing  collections  of  lymphoid 
tissue  and  nutrient  vessels.  Next  to  this  lies  the  mus- 
cidaris  mucosa  followed  by  the  external  or  submucous 
coat  containing  the  mucous  glands  and  external  to 
this  is  the  cartilage,  where  it  exists. 

The  two  bronchi  divide,  the  right  into  three  and  the 
left  into  two  branches  for  the  corresponding  lobes  of 
the  lungs.  Each  of  these  primary  bronchi  again  di- 
vides and  these  smaller  tubes  again  divide,  the  process 
being  repeated  until  the  terminal  bronchioles  are 
reached.  As  this  division  proceeds  the  cartilage  is  lost, 
then  the  mucous  coat  and  its  glands  disappear  and 
lastly  the  muscular  coat  ceases,  the  cilia  disappear,  and 
the  epithelium  becomes  cuboidal  in  form.  Each  bron- 
chiole has  now  apparently  dilated  into  a  wide  space 
termed  an  infundibulum  whose  walls  are  hollowed  out 
into  a  number  of  air  cells  or  alveoli  lined  by  a  single 


HISTOLOGY 


217 


n^T*~, 


Fig.   34. — Diagram  of  the  ending  of  a  bronchial  tube. 

layer  of  flat  pavement  epithelium  supported  on  a  fibro- 
elastic  tissue  framework  carrying  a  large  number  of 
capillaries. 

The  bronchial  arteries,  which  carry  nutrient  blood  to 
the  lungs,  with  the  bronchial  veins  for  the  return  circu- 
lation, follow  the  bronchi.  Entering  each  lung,  near  the 


218  ANATOMY   FOR   NURSES 

middle  of  its  inner  surface,  is  a  pulmonary  artery.  This 
artery  carries  venous  blood.  Its  subdivisions  follow  the 
bronchioles  until  its  capillaries  form  a  rich  network 
around  every  alveolus  and  the  C02  in  the  blood  is  thus 
brought  into  intimate  relationship  with  the  0  in  the  air 
cells.  The  capillaries  of  the  pulmonary  veins  take  up 
the  blood  after  C02  has  been  exchanged  for  0  and  unite 
to  form  radicles  which  unite  to  form  the  veins  which  in 
turn  form  the  pulmonary  veins  which  convey  the  oxygen- 
charged  blood  to  the  left  side  of  the  heart. 

The  union  of  many  primary  air  sacs  forms  a  lobule 
and  the  lobules  are  combined  until  a  lobe  of  the  lung  is 
formed. 

Each  lung  is  lined  on  its  exterior  by  a  serous  mem- 
brane, the  pleura,  covered  on  its  superficial  surface  by 
endothelium  resting  on  a  fibroelastic  layer  which  sends 
septa  into  the  lungs  to  divide  them  into  lobes  and  ulti- 
matelv  into  lobules. 


INDEX 


Alxlomeii,  91 
Abdomina]  aorta,  114 

viscera,  91 

Acromion  process,   32 
Alimentary  canal,  90 
Ankle  joint,  61 
Anterior  fossa  of  skull,  51 

region,  skull,  47 
Antrum    Highmore,    47 
Anus,  96 
Aorta,   112 

abdominal,  114 

ascending,  112 

thoracic,  113 

transverse,  113 
Appendix,  vermiform,  94 
Aqueous  humor,  173 
Arachnoid  membrane,  141 
Arm,  arteries,  126 

muscles,  80 

nerves,  160 

veins,  135 
Artery,  or  arteries,  107 

axillary,  125 

basilar,  148 

brachial,  126 

calcanean,  133 

carotid,    external,    121 
internal,  123 
left,  120 
right,  120 

circumflex,  126 

colica  dextra,  117 
media,  117 
sinistra,  117 

coronary,  112 

digital,  128 

facial,  121 

femoral,    131 

gastric,  115 

gluteal,  130 

hepatic,  115 


Artery,  or  arteries — ContM 

iliac,  common,  129 
external,  130 
internal,  129 

innominate,  119 

internal  mammary,  125 
maxillary,  122  * 
plantar,  133 

lingual,  121 

ophthalmic,  123 

phrenic,  144 

plantar,  133 

popliteal,  132 

pulmonary,  109 

radial,  127 

renal,  118 

subclavian,   124 

temporal,  122 

thyroid  axis,  124 

tibial,  anterior,  132 
posterior,  133 

ulnar,  128 

vertebral,  124 
Articulation,  ankle,   61 

carpal,  64 

costo-vertebral,  56 

elbow,  59 

hip,  57 

jaw,  63 

knee,  60 

pelvis,  64 

shoulder,  57 

vertebral,  54 

wrist,  62 

Articulations,  general,  52 
Ascending  colon,  94 
Astragalus,  43 
Atlas,  26 

Auditory  nerve,  153 
Axilla,  126 
Axillary  artery,  125 

vein,  136 
Axis,  26 


219 


220 


INDEX 


B 

Base  of  brain,  145 

skull,  51 

Basilic  vein,  136 
Bladder,  98 
Bone,  or  bones, 

astragalus,  43 

atlas,   26 

axis,  26 

calcaneum,  42 

carpal,  41 

clavicle,  30 

coccyx,  27 

cranial,  45 

cuboid,  43 

femur,  36 

fibula,  40 

frontal,  47 

humerus,  35 

hyoid,  45 

ilium,  32 

inferior  maxillary,  50 
turbinate,  50 

innominate,  32 

ischium,  32 

nasal,  47 

occipital,  45 

patella,  39 

radius,  37 

rib,  27 

sacrum,  27 

scaphoid,  44 

scapula,  31 

sternum,  27 

tarsal,  42 

tibia,  39 

ulna,  38 
Brain,  141 

base  of,  145 

convolutions,  142 

membranes,  140 
Bronchi,  105 

C 

Capsular  ligaments,  55 
Celiac  axis,  115 
Cerebellum,  146 
Cerebrum,  142 
Clavicle,  30 
Cranial  bones,  45 

nerves,  eighth,  153 
eleventh,  155 


Cranial  nerves — Cont'd 

fifth,  150 

first,  149 

fourth,  150 

ninth,  153 

second,  150 

seventh,  152 

sixth,  150 

tenth,  153 

third,  150 

twelfth,  155 
Crystalline  lens,  173 

D 

Duodenum,  93 

E 

Ear,  174 
Elbow  joint,  59 
Epiglottis,  179 
Esophagus,  91 
Eye,   171 

F 

Face,  arteries  of,  121 

bones,  47 

muscles,  75 
Fauces,  90 

Female  generative  organs,  99 
Femoral  artery,  131 
Fifth  nerve,  150 
First  nerve,  149 
Foot,  arteries  of,  137 

bones,  43 

muscles,  89 

nerves,  165 
Fossa  of  skull,  51 

G 

Gangliated  cord,  167 
H 

Hand,  arteries,  128 

bones,  41 

muscles,  83 
Heart,  102 
Hip  joint,  57 
Humerus,   35 

I 

Ileum,  94 
Iliac  arteries,  129 


INDEX 


221 


Ilium,  32 

Inferior  vena  cava,  135 

Intestines,  large,  94 

small,  94 
Ischium,  32 

K 

Kidney,  98 

structure  of,  213 
Knee  joint,  60 


Larynx,  cartilages,  177 

ligaments,  179 

muscles,  180 
Ligaments,  52 

ankle,  61 

elbow,  59 

hip,  57 

jaw,  63 

knee,  60 

pelvis,  64 

shoulder,  57 

wrist,  62 
Liver,  96 

structure  of,  207 
Lungs,  105 

structure  of,  217 
Lymphatics,  138 

M 

Manubrium,  27 
Mediastinum,  105 
Medulla  oblongata,  146 
Membranes  of  brain,  140 

of  cord,  147 
Mouth,  90 
Muscle,  or  muscles,  67 

adductor  group,  85 

arytenoid,  180 

biceps,  arm,  81 
thigh,  85 

bronchialis  anticus,  81 

constrictors  of  pharynx,  91 

coraco-brachialis,  81 

crico-arytenoid,  181 

crico-thyoid,  181 

deltoid/  80 

diaphragm,  71 

digastric,  74 

erector  spinal,  79 


Muscle,  or  muscles — Cont  'd 
extensors,  forearm,  82 

leg,  88 
flexors,  81 
of  abdomen,  68 
of  arm,  79 
of  back,  77 
of  eyeball,  75 
of  face,  75 
of  forearm,  81 
of  foot,  89 
of  hand,  83 
of  hip,   84 
of  leg,  87 
of  neck,  73 
of  thigh,  85 
pectoral,  72 
psoas,  85 
pterygoid,  75 

N 

Xeck,  arteries,  120 

muscles,  73 

veins,  137 
Nerve,  or  nerves,  149 

auditory,  153 

brachial  plexus,  159 

cervical  plexus,  157 

chorda  tympani,  152 

ciliary,  167 

circumflex,  162 

dental,  157 

dorsal,  157 

eighth  pair,  153 

eleventh  pair,  155 

facial,  152 

fifth,  150 

fourth,  150 

frontal,  151 

glosso-pharyngeal,  153 

great  sciatic,  164 

gustatory,  152 

hypoglossal,  155 

intercostal,  157 

laryngeal,  recurrent,  154 

lumbar  plexus,  162 

median,  160 

musculo-spiral,  162 

ninth,  153 

olfactory,   149 

ophthalmic,  151 

optic,  150 


222 


INDEX 


Nerve,  or  nerves  —  Cont'd 

Shoulder  joint,  57 

phrenic,   158 

Skull,  45 

plantar,  165 

Spinal  cord,  147 

pneumogastric,  153 

histology,  201 

popliteal,  or  peroneal,  165 

nerves,  156 

radial,  162 

Spine,  22 

sacral,  plexus,  164 

Spleen,  97 

saphenous,  163 

structure,  204 

sciatic,  164 

Sternum,  27 

seventh,  152 

Stomach,  93 

sixth,  150 

structure,   211 

sympathetic,  166 

Subclavian  artery,  left,  120 

tenth,  153 

right,  124 

third,  150 

Sympathetic  nerves,  166 

thoracic,  157 

tibial,  166 

T 

twelfth,  155 

Testes,  101 

ulnar,  161 

Thorax,  27 

vagus,  153 

Thyroid  cartilage,  178 

Trachea,  105 

O 

U 

Obturator  artery,  130 

Ulna,  38 

muscles,  84 

Ulnar  artery,  128 

nerves,  164 

nerve,  161  . 

Os  calcis,  42 

Ureter,  98 

/ 

p 

Urethra,  female,  98 

male,  98 

Palmar  arteries,  128 

Uterus,  99 

muscles,  83 

Pancreas,  97 

V 

structure  of,  207 

Vagina,  100 

Patella,  39 

Vein,  or  veins,  134 

Pelvis,  33 

axillary,  136 

ligaments  of,  64 

basillic,  126 

viscera  of,  99 

cava,  inferior,  135 

Pharynx,  91 

superior,  138 

Pleura,  104 

cephalic,  136 

R 

femoral,  135 

iliac    135 

Radial  artery,  127 

innominate,   138 

nerve,  162 
Radius,  37 
Rectum,  96 
Renal  artery  118 
Retina,  173 

jugular,  137 
popliteal,  135 
portal,  118 
saphenous,  134 
subclavian,  137 

Ribs,  27 

Vertebral,  23 

Vertebral  column,  22 

Sacral  plexus,  164 

Viscera,  91 

Sacrum,  28 

Vocal  cords,  180 

Scapula,  31 

Sciatic  artery,  130 

nerve,  164 

Willis,  circle  of,  148 

UNIVERSITY  OF  CALIFORNIA  MEDICAL  SCHOOL  LIBRARY 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

I 


SEP  I 
M"K  i  8  1924 
JUN  2    1924 
AUG    4  1924 

OCT  22 


DHL 


N'OV  1  -  1928 

DEC  1  7  1330 
V  23  I! 


EEfi 

<;  1  1942 


OECl-  1943 
ll  5944 


1  7 


1  4  194S 


lm-11,'18 


University  of  California  Medical  School  Library 


